diff --git a/chopper/CHANGELOG.md b/chopper/CHANGELOG.md
index fbe89040..e78e1909 100644
--- a/chopper/CHANGELOG.md
+++ b/chopper/CHANGELOG.md
@@ -1,22 +1,8 @@
 # Changelog
 
-## 4.0.6
+## 5.0.0
 
-- FieldMap added
-- Example migrated to null safety / Angular removed
-
-## 4.0.5
-
-- Add additional param for the authenticator
-
-## 4.0.4
-
-- Fix for authenticator usage
-
-## 4.0.3
-
-- Fix for authenticator usage
-- Null-safety fixes
+- API breaking changes (FutureOr)
 
 ## 4.0.1
 
diff --git a/chopper/analysis_options.yaml b/chopper/analysis_options.yaml
index d4fcc1ad..7f5a674f 100644
--- a/chopper/analysis_options.yaml
+++ b/chopper/analysis_options.yaml
@@ -1 +1,34 @@
-include: package:pedantic/analysis_options.yaml
\ No newline at end of file
+include: package:lints/recommended.yaml
+
+analyzer:
+  exclude:
+    - "**.g.dart"
+    - "**.chopper.dart"
+    - "**.mocks.dart"
+    - "example/**"
+  plugins:
+    - dart_code_metrics
+
+dart_code_metrics:
+  metrics:
+    cyclomatic-complexity: 20
+    number-of-arguments: 4
+    maximum-nesting-level: 5
+    number-of-parameters: 7
+  metrics-exclude:
+    - test/**
+  rules:
+    - newline-before-return
+    - no-boolean-literal-compare
+    - no-empty-block
+    - prefer-trailing-comma
+    - prefer-conditional-expressions
+    - no-equal-then-else
+  anti-patterns:
+    - long-method
+    - long-parameter-list
+
+linter:
+  rules:
+    avoid_print: true
+    prefer_single_quotes: true
diff --git a/chopper/example/definition.chopper.dart b/chopper/example/definition.chopper.dart
index 0a26d4a8..f43a754d 100644
--- a/chopper/example/definition.chopper.dart
+++ b/chopper/example/definition.chopper.dart
@@ -6,7 +6,7 @@ part of 'definition.dart';
 // ChopperGenerator
 // **************************************************************************
 
-// ignore_for_file: always_put_control_body_on_new_line, always_specify_types, prefer_const_declarations
+// ignore_for_file: always_put_control_body_on_new_line, always_specify_types, prefer_const_declarations, unnecessary_brace_in_string_interps
 class _$MyService extends MyService {
   _$MyService([ChopperClient? client]) {
     if (client == null) return;
@@ -18,7 +18,7 @@ class _$MyService extends MyService {
 
   @override
   Future<Response<dynamic>> getResource(String id) {
-    final $url = '/resources/$id';
+    final $url = '/resources/${id}';
     final $request = Request('GET', $url, client.baseUrl);
     return client.send<dynamic, dynamic>($request);
   }
diff --git a/chopper/example/definition.dart b/chopper/example/definition.dart
index 5103ca4d..ef8fcf9d 100644
--- a/chopper/example/definition.dart
+++ b/chopper/example/definition.dart
@@ -1,4 +1,5 @@
 import 'dart:async';
+
 import 'package:chopper/chopper.dart';
 
 part 'definition.chopper.dart';
diff --git a/chopper/example/main.dart b/chopper/example/main.dart
index d1831859..16f66abc 100644
--- a/chopper/example/main.dart
+++ b/chopper/example/main.dart
@@ -1,4 +1,5 @@
 import 'package:chopper/chopper.dart';
+
 import 'definition.dart';
 
 Future<void> main() async {
@@ -6,7 +7,7 @@ Future<void> main() async {
     baseUrl: 'http://localhost:8000',
     services: [
       // the generated service
-      MyService.create(ChopperClient())
+      MyService.create(ChopperClient()),
     ],
     converter: JsonConverter(),
   );
diff --git a/chopper/lib/chopper.dart b/chopper/lib/chopper.dart
index 9d1d9826..c004d675 100644
--- a/chopper/lib/chopper.dart
+++ b/chopper/lib/chopper.dart
@@ -6,8 +6,8 @@ library chopper;
 export 'src/annotations.dart';
 export 'src/authenticator.dart';
 export 'src/base.dart';
+export 'src/constants.dart';
 export 'src/interceptor.dart';
 export 'src/request.dart';
 export 'src/response.dart';
 export 'src/utils.dart' hide mapToQuery;
-export 'src/constants.dart';
diff --git a/chopper/lib/src/annotations.dart b/chopper/lib/src/annotations.dart
index 1bd3389d..dafed63b 100644
--- a/chopper/lib/src/annotations.dart
+++ b/chopper/lib/src/annotations.dart
@@ -1,8 +1,10 @@
 import 'dart:async';
+
 import 'package:meta/meta.dart';
+
+import 'constants.dart';
 import 'request.dart';
 import 'response.dart';
-import 'constants.dart';
 
 /// Defines a Chopper API.
 ///
@@ -171,15 +173,10 @@ class Method {
 @immutable
 class Get extends Method {
   const Get({
-    bool optionalBody = true,
-    String path = '',
-    Map<String, String> headers = const {},
-  }) : super(
-          HttpMethod.Get,
-          optionalBody: optionalBody,
-          path: path,
-          headers: headers,
-        );
+    super.optionalBody = true,
+    super.path,
+    super.headers,
+  }) : super(HttpMethod.Get);
 }
 
 /// Defines a method as an HTTP POST request.
@@ -188,30 +185,20 @@ class Get extends Method {
 @immutable
 class Post extends Method {
   const Post({
-    bool optionalBody = false,
-    String path = '',
-    Map<String, String> headers = const {},
-  }) : super(
-          HttpMethod.Post,
-          optionalBody: optionalBody,
-          path: path,
-          headers: headers,
-        );
+    super.optionalBody,
+    super.path,
+    super.headers,
+  }) : super(HttpMethod.Post);
 }
 
 /// Defines a method as an HTTP DELETE request.
 @immutable
 class Delete extends Method {
   const Delete({
-    bool optionalBody = true,
-    String path = '',
-    Map<String, String> headers = const {},
-  }) : super(
-          HttpMethod.Delete,
-          optionalBody: optionalBody,
-          path: path,
-          headers: headers,
-        );
+    super.optionalBody = true,
+    super.path,
+    super.headers,
+  }) : super(HttpMethod.Delete);
 }
 
 /// Defines a method as an HTTP PUT request.
@@ -220,15 +207,10 @@ class Delete extends Method {
 @immutable
 class Put extends Method {
   const Put({
-    bool optionalBody = false,
-    String path = '',
-    Map<String, String> headers = const {},
-  }) : super(
-          HttpMethod.Put,
-          optionalBody: optionalBody,
-          path: path,
-          headers: headers,
-        );
+    super.optionalBody,
+    super.path,
+    super.headers,
+  }) : super(HttpMethod.Put);
 }
 
 /// Defines a method as an HTTP PATCH request.
@@ -236,44 +218,29 @@ class Put extends Method {
 @immutable
 class Patch extends Method {
   const Patch({
-    bool optionalBody = false,
-    String path = '',
-    Map<String, String> headers = const {},
-  }) : super(
-          HttpMethod.Patch,
-          optionalBody: optionalBody,
-          path: path,
-          headers: headers,
-        );
+    super.optionalBody,
+    super.path,
+    super.headers,
+  }) : super(HttpMethod.Patch);
 }
 
 /// Defines a method as an HTTP HEAD request.
 @immutable
 class Head extends Method {
   const Head({
-    bool optionalBody = true,
-    String path = '',
-    Map<String, String> headers = const {},
-  }) : super(
-          HttpMethod.Head,
-          optionalBody: optionalBody,
-          path: path,
-          headers: headers,
-        );
+    super.optionalBody = true,
+    super.path,
+    super.headers,
+  }) : super(HttpMethod.Head);
 }
 
 @immutable
 class Options extends Method {
   const Options({
-    bool optionalBody = true,
-    String path = '',
-    Map<String, String> headers = const {},
-  }) : super(
-          HttpMethod.Options,
-          optionalBody: optionalBody,
-          path: path,
-          headers: headers,
-        );
+    super.optionalBody = true,
+    super.path,
+    super.headers,
+  }) : super(HttpMethod.Options);
 }
 
 /// A function that should convert the body of a [Request] to the HTTP representation.
@@ -377,6 +344,7 @@ class Multipart {
 @immutable
 class Part {
   final String? name;
+
   const Part([this.name]);
 }
 
diff --git a/chopper/lib/src/authenticator.dart b/chopper/lib/src/authenticator.dart
index db225a49..d69e6d76 100644
--- a/chopper/lib/src/authenticator.dart
+++ b/chopper/lib/src/authenticator.dart
@@ -5,6 +5,9 @@ import 'package:chopper/chopper.dart';
 /// This method should return a [Request] that includes credentials to satisfy an authentication challenge received in
 /// [response]. It should return `null` if the challenge cannot be satisfied.
 abstract class Authenticator {
-  FutureOr<Request?> authenticate(Request request, Response response,
-      [Request? originalRequest]);
+  FutureOr<Request?> authenticate(
+    Request request,
+    Response response, [
+    Request? originalRequest,
+  ]);
 }
diff --git a/chopper/lib/src/base.dart b/chopper/lib/src/base.dart
index b0f90848..3fa4e998 100644
--- a/chopper/lib/src/base.dart
+++ b/chopper/lib/src/base.dart
@@ -1,19 +1,20 @@
 import 'dart:async';
-import 'package:meta/meta.dart';
+
 import 'package:http/http.dart' as http;
-import 'constants.dart';
+import 'package:meta/meta.dart';
 
+import 'annotations.dart';
+import 'authenticator.dart';
+import 'constants.dart';
 import 'interceptor.dart';
 import 'request.dart';
 import 'response.dart';
-import 'annotations.dart';
-import 'authenticator.dart';
 import 'utils.dart';
 
 Type _typeOf<T>() => T;
 
 @visibleForTesting
-final allowedInterceptorsType = <Type>[
+final List<Type> allowedInterceptorsType = [
   RequestInterceptor,
   RequestInterceptorFunc,
   ResponseInterceptor,
@@ -120,7 +121,7 @@ class ChopperClient {
     Iterable<ChopperService> services = const [],
   })  : httpClient = client ?? http.Client(),
         _clientIsInternal = client == null {
-    if (interceptors.every(_isAnInterceptor) == false) {
+    if (!interceptors.every(_isAnInterceptor)) {
       throw ArgumentError(
         'Unsupported type for interceptors, it only support the following types:\n'
         '${allowedInterceptorsType.join('\n - ')}',
@@ -162,31 +163,28 @@ class ChopperClient {
   /// final todoService = chopper.getService<TodosListService>();
   /// ```
   ServiceType getService<ServiceType extends ChopperService>() {
-    final serviceType = _typeOf<ServiceType>();
+    final Type serviceType = _typeOf<ServiceType>();
     if (serviceType == dynamic || serviceType == ChopperService) {
       throw Exception(
-          'Service type should be provided, `dynamic` is not allowed.');
+        'Service type should be provided, `dynamic` is not allowed.',
+      );
     }
-    final service = _services[serviceType];
+    final ChopperService? service = _services[serviceType];
     if (service == null) {
       throw Exception('Service of type \'$serviceType\' not found.');
     }
+
     return service as ServiceType;
   }
 
-  Future<Request> _encodeRequest(Request request) async {
-    return converter?.convertRequest(request) ?? request;
-  }
+  Future<Request> _encodeRequest(Request request) async =>
+      converter?.convertRequest(request) ?? request;
 
   Future<Response<BodyType>> _decodeResponse<BodyType, InnerType>(
     Response response,
     Converter withConverter,
-  ) async {
-    final converted =
-        await withConverter.convertResponse<BodyType, InnerType>(response);
-
-    return converted;
-  }
+  ) async =>
+      await withConverter.convertResponse<BodyType, InnerType>(response);
 
   Future<Request> _interceptRequest(Request req) async {
     final body = req.body;
@@ -203,6 +201,7 @@ class ChopperClient {
       'Interceptors should not transform the body of the request'
       'Use Request converter instead',
     );
+
     return req;
   }
 
@@ -242,11 +241,7 @@ class ChopperClient {
       error = errorRes?.error ?? errorRes?.body;
     }
 
-    return Response<BodyType>(
-      response.base,
-      null,
-      error: error,
-    );
+    return Response<BodyType>(response.base, null, error: error);
   }
 
   Future<Response<BodyType>> _handleSuccessResponse<BodyType, InnerType>(
@@ -269,17 +264,12 @@ class ChopperClient {
   Future<Request> _handleRequestConverter(
     Request request,
     ConvertRequest? requestConverter,
-  ) async {
-    if (request.body != null || request.parts.isNotEmpty) {
-      if (requestConverter != null) {
-        request = await requestConverter(request);
-      } else {
-        request = (await _encodeRequest(request));
-      }
-    }
-
-    return request;
-  }
+  ) async =>
+      request.body != null || request.parts.isNotEmpty
+          ? requestConverter != null
+              ? await requestConverter(request)
+              : await _encodeRequest(request)
+          : request;
 
   /// Sends a pre-build [Request], applying all provided [Interceptor]s and
   /// [Converter]s.
@@ -298,8 +288,9 @@ class ChopperClient {
     ConvertRequest? requestConverter,
     ConvertResponse? responseConverter,
   }) async {
-    var req = await _handleRequestConverter(request, requestConverter);
-    req = await _interceptRequest(req);
+    var req = await _interceptRequest(
+      await _handleRequestConverter(request, requestConverter),
+    );
     _requestController.add(req);
 
     final streamRes = await httpClient.send(await req.toBaseRequest());
@@ -324,27 +315,28 @@ class ChopperClient {
           return _processResponse(res);
         } else {
           res = await _handleErrorResponse<BodyType, InnerType>(res);
+
           return _processResponse(res);
         }
       }
     }
 
-    if (_responseIsSuccessful(res.statusCode)) {
-      res = await _handleSuccessResponse<BodyType, InnerType>(
-        res,
-        responseConverter,
-      );
-    } else {
-      res = await _handleErrorResponse<BodyType, InnerType>(res);
-    }
+    res = _responseIsSuccessful(res.statusCode)
+        ? await _handleSuccessResponse<BodyType, InnerType>(
+            res,
+            responseConverter,
+          )
+        : await _handleErrorResponse<BodyType, InnerType>(res);
 
     return _processResponse(res);
   }
 
   Future<Response<BodyType>> _processResponse<BodyType, InnerType>(
-      dynamic res) async {
+    dynamic res,
+  ) async {
     res = await _interceptResponse<BodyType, InnerType>(res);
     _responseController.add(res);
+
     return res;
   }
 
diff --git a/chopper/lib/src/constants.dart b/chopper/lib/src/constants.dart
index 21f388aa..e7e8faec 100644
--- a/chopper/lib/src/constants.dart
+++ b/chopper/lib/src/constants.dart
@@ -1,9 +1,11 @@
-const contentTypeKey = 'content-type';
-const jsonHeaders = 'application/json';
-const formEncodedHeaders = 'application/x-www-form-urlencoded';
+// ignore_for_file: constant_identifier_names
+
+const String contentTypeKey = 'content-type';
+const String jsonHeaders = 'application/json';
+const String formEncodedHeaders = 'application/x-www-form-urlencoded';
 
 // Represent the header for a json api response https://jsonapi.org/#mime-types
-const jsonApiHeaders = 'application/vnd.api+json';
+const String jsonApiHeaders = 'application/vnd.api+json';
 
 class HttpMethod {
   static const String Get = 'GET';
diff --git a/chopper/lib/src/interceptor.dart b/chopper/lib/src/interceptor.dart
index 5c89cbc3..9d393afc 100644
--- a/chopper/lib/src/interceptor.dart
+++ b/chopper/lib/src/interceptor.dart
@@ -1,12 +1,13 @@
 import 'dart:async';
 import 'dart:convert';
-import 'package:meta/meta.dart';
+
 import 'package:http/http.dart' as http;
+import 'package:meta/meta.dart';
 
+import 'constants.dart';
 import 'request.dart';
 import 'response.dart';
 import 'utils.dart';
-import 'constants.dart';
 
 /// An interface for implementing response interceptors.
 ///
@@ -136,14 +137,11 @@ typedef RequestInterceptorFunc = FutureOr<Request> Function(Request request);
 class CurlInterceptor implements RequestInterceptor {
   @override
   Future<Request> onRequest(Request request) async {
-    final baseRequest = await request.toBaseRequest();
-    final method = baseRequest.method;
-    final url = baseRequest.url.toString();
-    final headers = baseRequest.headers;
-    var curl = '';
-    curl += 'curl';
-    curl += ' -v';
-    curl += ' -X $method';
+    final http.BaseRequest baseRequest = await request.toBaseRequest();
+    final String method = baseRequest.method;
+    final String url = baseRequest.url.toString();
+    final Map<String, String> headers = baseRequest.headers;
+    String curl = 'curl -v -X $method';
     headers.forEach((k, v) {
       curl += ' -H \'$k: $v\'';
     });
@@ -154,8 +152,9 @@ class CurlInterceptor implements RequestInterceptor {
         curl += ' -d \'$body\'';
       }
     }
-    curl += ' \"$url\"';
+    curl += ' "$url"';
     chopperLogger.info(curl);
+
     return request;
   }
 }
@@ -172,11 +171,11 @@ class HttpLoggingInterceptor
     implements RequestInterceptor, ResponseInterceptor {
   @override
   FutureOr<Request> onRequest(Request request) async {
-    final base = await request.toBaseRequest();
+    final http.BaseRequest base = await request.toBaseRequest();
     chopperLogger.info('--> ${base.method} ${base.url}');
     base.headers.forEach((k, v) => chopperLogger.info('$k: $v'));
 
-    var bytes = '';
+    String bytes = '';
     if (base is http.Request) {
       final body = base.body;
       if (body.isNotEmpty) {
@@ -186,17 +185,18 @@ class HttpLoggingInterceptor
     }
 
     chopperLogger.info('--> END ${base.method}$bytes');
+
     return request;
   }
 
   @override
   FutureOr<Response> onResponse(Response response) {
-    final base = response.base.request;
+    final http.BaseRequest? base = response.base.request;
     chopperLogger.info('<-- ${response.statusCode} ${base!.url}');
 
     response.base.headers.forEach((k, v) => chopperLogger.info('$k: $v'));
 
-    var bytes;
+    String bytes = '';
     if (response.base is http.Response) {
       final resp = response.base as http.Response;
       if (resp.body.isNotEmpty) {
@@ -206,6 +206,7 @@ class HttpLoggingInterceptor
     }
 
     chopperLogger.info('--> END ${base.method}$bytes');
+
     return response;
   }
 }
@@ -228,29 +229,27 @@ class JsonConverter implements Converter, ErrorConverter {
   const JsonConverter();
 
   @override
-  Request convertRequest(Request request) {
-    final req = applyHeader(
-      request,
-      contentTypeKey,
-      jsonHeaders,
-      override: false,
-    );
-
-    return encodeJson(req);
-  }
+  Request convertRequest(Request request) => encodeJson(
+        applyHeader(
+          request,
+          contentTypeKey,
+          jsonHeaders,
+          override: false,
+        ),
+      );
 
   Request encodeJson(Request request) {
-    var contentType = request.headers[contentTypeKey];
-    if (contentType != null && contentType.contains(jsonHeaders)) {
-      return request.copyWith(body: json.encode(request.body));
-    }
-    return request;
+    final String? contentType = request.headers[contentTypeKey];
+
+    return (contentType?.contains(jsonHeaders) ?? false)
+        ? request.copyWith(body: json.encode(request.body))
+        : request;
   }
 
-  Response decodeJson<BodyType, InnerType>(Response response) {
-    final supportedContentTypes = [jsonHeaders, jsonApiHeaders];
+  FutureOr<Response> decodeJson<BodyType, InnerType>(Response response) async {
+    final List<String> supportedContentTypes = [jsonHeaders, jsonApiHeaders];
 
-    final contentType = response.headers[contentTypeKey];
+    final String? contentType = response.headers[contentTypeKey];
     var body = response.body;
 
     if (supportedContentTypes.contains(contentType)) {
@@ -264,7 +263,7 @@ class JsonConverter implements Converter, ErrorConverter {
       body = utf8.decode(response.bodyBytes);
     }
 
-    body = _tryDecodeJson(body);
+    body = await tryDecodeJson(body);
     if (isTypeOf<BodyType, Iterable<InnerType>>()) {
       body = body.cast<InnerType>();
     } else if (isTypeOf<BodyType, Map<String, InnerType>>()) {
@@ -275,32 +274,35 @@ class JsonConverter implements Converter, ErrorConverter {
   }
 
   @override
-  Response<BodyType> convertResponse<BodyType, InnerType>(Response response) {
-    return decodeJson<BodyType, InnerType>(response) as Response<BodyType>;
-  }
+  FutureOr<Response<BodyType>> convertResponse<BodyType, InnerType>(
+    Response response,
+  ) async =>
+      (await decodeJson<BodyType, InnerType>(response)) as Response<BodyType>;
 
-  dynamic _tryDecodeJson(String data) {
+  @protected
+  FutureOr<dynamic> tryDecodeJson(String data) {
     try {
       return json.decode(data);
     } catch (e) {
       chopperLogger.warning(e);
+
       return data;
     }
   }
 
   @override
-  Response convertError<BodyType, InnerType>(Response response) =>
-      decodeJson(response);
+  FutureOr<Response> convertError<BodyType, InnerType>(
+    Response response,
+  ) async =>
+      await decodeJson(response);
 
-  static Response<BodyType> responseFactory<BodyType, InnerType>(
+  static FutureOr<Response<BodyType>> responseFactory<BodyType, InnerType>(
     Response response,
-  ) {
-    return const JsonConverter().convertResponse<BodyType, InnerType>(response);
-  }
+  ) =>
+      const JsonConverter().convertResponse<BodyType, InnerType>(response);
 
-  static Request requestFactory(Request request) {
-    return const JsonConverter().convertRequest(request);
-  }
+  static Request requestFactory(Request request) =>
+      const JsonConverter().convertRequest(request);
 }
 
 /// A [Converter] implementation that converts only [Request]s having a [Map] as their body.
@@ -314,7 +316,7 @@ class FormUrlEncodedConverter implements Converter, ErrorConverter {
 
   @override
   Request convertRequest(Request request) {
-    var req = applyHeader(
+    final Request req = applyHeader(
       request,
       contentTypeKey,
       formEncodedHeaders,
@@ -324,22 +326,19 @@ class FormUrlEncodedConverter implements Converter, ErrorConverter {
     if (req.body is Map<String, String>) return req;
 
     if (req.body is Map) {
-      final body = <String, String>{};
-
-      req.body.forEach((key, val) {
-        if (val != null) {
-          body[key.toString()] = val.toString();
-        }
+      return req.copyWith(body: <String, String>{
+        for (final MapEntry e in req.body.entries)
+          if (e.value != null) e.key.toString(): e.value.toString(),
       });
-
-      req = req.copyWith(body: body);
     }
 
     return req;
   }
 
   @override
-  Response<BodyType> convertResponse<BodyType, InnerType>(Response response) =>
+  FutureOr<Response<BodyType>> convertResponse<BodyType, InnerType>(
+    Response response,
+  ) =>
       response as Response<BodyType>;
 
   @override
diff --git a/chopper/lib/src/request.dart b/chopper/lib/src/request.dart
index 88a7ed05..8378e276 100644
--- a/chopper/lib/src/request.dart
+++ b/chopper/lib/src/request.dart
@@ -1,10 +1,11 @@
 import 'dart:async';
 import 'dart:convert';
 
-import 'package:meta/meta.dart';
 import 'package:http/http.dart' as http;
-import 'utils.dart';
+import 'package:meta/meta.dart';
+
 import 'constants.dart';
+import 'utils.dart';
 
 /// This class represents an HTTP request that can be made with Chopper.
 @immutable
@@ -54,7 +55,7 @@ class Request {
 
   Uri _buildUri() => buildUri(baseUrl, url, parameters);
 
-  Map<String, String> _buildHeaders() => Map<String, String>.from(headers);
+  Map<String, String> _buildHeaders() => {...headers};
 
   /// Converts this Chopper Request into a [http.BaseRequest].
   ///
@@ -65,32 +66,18 @@ class Request {
   ///   - [http.MultipartRequest] if [multipart] is true
   ///   - or a [http.Request]
   Future<http.BaseRequest> toBaseRequest() async {
-    final uri = _buildUri();
-    final heads = _buildHeaders();
+    final Uri uri = _buildUri();
+    final Map<String, String> heads = _buildHeaders();
 
     if (body is Stream<List<int>>) {
-      return toStreamedRequest(
-        body,
-        method,
-        uri,
-        heads,
-      );
+      return toStreamedRequest(body, method, uri, heads);
     }
 
     if (multipart) {
-      return toMultipartRequest(
-        parts,
-        method,
-        uri,
-        heads,
-      );
+      return toMultipartRequest(parts, method, uri, heads);
     }
-    return toHttpRequest(
-      body,
-      method,
-      uri,
-      heads,
-    );
+
+    return toHttpRequest(body, method, uri, heads);
   }
 }
 
@@ -117,33 +104,30 @@ class PartValue<T> {
 /// Represents a file part in a multipart request.
 @immutable
 class PartValueFile<T> extends PartValue<T> {
-  PartValueFile(String name, T value) : super(name, value);
+  const PartValueFile(super.name, super.value);
 }
 
 /// Builds a valid URI from [baseUrl], [url] and [parameters].
 ///
 /// If [url] starts with 'http://' or 'https://', baseUrl is ignored.
 Uri buildUri(String baseUrl, String url, Map<String, dynamic> parameters) {
-  var uri;
-  if (url.startsWith('http://') || url.startsWith('https://')) {
-    // If the request's url is already a fully qualified URL, we can use it
-    // as-is and ignore the baseUrl.
-    uri = Uri.parse(url);
-  } else {
-    if (!baseUrl.endsWith('/') && !url.startsWith('/')) {
-      uri = Uri.parse('$baseUrl/$url');
-    } else {
-      uri = Uri.parse('$baseUrl$url');
-    }
-  }
-
-  var query = mapToQuery(parameters);
+  // If the request's url is already a fully qualified URL, we can use it
+  // as-is and ignore the baseUrl.
+  Uri uri = url.startsWith('http://') || url.startsWith('https://')
+      ? Uri.parse(url)
+      : !baseUrl.endsWith('/') && !url.startsWith('/')
+          ? Uri.parse('$baseUrl/$url')
+          : Uri.parse('$baseUrl$url');
+
+  String query = mapToQuery(parameters);
   if (query.isNotEmpty) {
     if (uri.hasQuery) {
       query += '&${uri.query}';
     }
+
     return uri.replace(query: query);
   }
+
   return uri;
 }
 
@@ -154,8 +138,8 @@ Future<http.Request> toHttpRequest(
   Uri uri,
   Map<String, String> headers,
 ) async {
-  final baseRequest = http.Request(method, uri);
-  baseRequest.headers.addAll(headers);
+  final http.Request baseRequest = http.Request(method, uri)
+    ..headers.addAll(headers);
 
   if (body != null) {
     if (body is String) {
@@ -168,6 +152,7 @@ Future<http.Request> toHttpRequest(
       throw ArgumentError.value('$body', 'body');
     }
   }
+
   return baseRequest;
 }
 
@@ -178,10 +163,10 @@ Future<http.MultipartRequest> toMultipartRequest(
   Uri uri,
   Map<String, String> headers,
 ) async {
-  final baseRequest = http.MultipartRequest(method, uri);
-  baseRequest.headers.addAll(headers);
+  final http.MultipartRequest baseRequest = http.MultipartRequest(method, uri)
+    ..headers.addAll(headers);
 
-  for (final part in parts) {
+  for (final PartValue part in parts) {
     if (part.value == null) continue;
 
     if (part.value is http.MultipartFile) {
@@ -210,6 +195,7 @@ Future<http.MultipartRequest> toMultipartRequest(
       baseRequest.fields[part.name] = part.value.toString();
     }
   }
+
   return baseRequest;
 }
 
@@ -220,11 +206,14 @@ Future<http.StreamedRequest> toStreamedRequest(
   Uri uri,
   Map<String, String> headers,
 ) async {
-  final req = http.StreamedRequest(method, uri);
-  req.headers.addAll(headers);
+  final http.StreamedRequest req = http.StreamedRequest(method, uri)
+    ..headers.addAll(headers);
 
-  bodyStream.listen(req.sink.add,
-      onDone: req.sink.close, onError: req.sink.addError);
+  bodyStream.listen(
+    req.sink.add,
+    onDone: req.sink.close,
+    onError: req.sink.addError,
+  );
 
   return req;
 }
diff --git a/chopper/lib/src/response.dart b/chopper/lib/src/response.dart
index e4d9a56f..1fc29fac 100644
--- a/chopper/lib/src/response.dart
+++ b/chopper/lib/src/response.dart
@@ -29,7 +29,7 @@ class Response<BodyType> {
   /// The body of the response if [isSuccessful] is false.
   final Object? error;
 
-  Response(this.base, this.body, {this.error});
+  const Response(this.base, this.body, {this.error});
 
   /// Makes a copy of this Response, replacing original values with the given ones.
   /// This method can also alter the type of the response body.
diff --git a/chopper/lib/src/utils.dart b/chopper/lib/src/utils.dart
index 21b0605f..e4d17f7d 100644
--- a/chopper/lib/src/utils.dart
+++ b/chopper/lib/src/utils.dart
@@ -39,16 +39,16 @@ Request applyHeaders(
   Map<String, String> headers, {
   bool override = true,
 }) {
-  final h = Map<String, String>.from(request.headers);
+  final Map<String, String> headersCopy = {...request.headers};
 
-  for (var k in headers.keys) {
-    var val = headers[k];
-    if (val == null) continue;
-    if (!override && h.containsKey(k)) continue;
-    h[k] = val;
+  for (String key in headers.keys) {
+    String? value = headers[key];
+    if (value == null) continue;
+    if (!override && headersCopy.containsKey(key)) continue;
+    headersCopy[key] = value;
   }
 
-  return request.copyWith(headers: h);
+  return request.copyWith(headers: headersCopy);
 }
 
 final chopperLogger = Logger('Chopper');
@@ -62,12 +62,11 @@ Iterable<_Pair<String, String>> _mapToQuery(
   Map<String, dynamic> map, {
   String? prefix,
 }) {
-  /// ignore: prefer_collection_literals
-  final pairs = Set<_Pair<String, String>>();
+  final Set<_Pair<String, String>> pairs = {};
 
   map.forEach((key, value) {
     if (value != null) {
-      var name = Uri.encodeQueryComponent(key);
+      String name = Uri.encodeQueryComponent(key);
 
       if (prefix != null) {
         name = '$prefix.$name';
@@ -77,11 +76,12 @@ Iterable<_Pair<String, String>> _mapToQuery(
         pairs.addAll(_iterableToQuery(name, value));
       } else if (value is Map<String, dynamic>) {
         pairs.addAll(_mapToQuery(value, prefix: name));
-      } else if (value.toString().isNotEmpty == true) {
+      } else if (value.toString().isNotEmpty) {
         pairs.add(_Pair<String, String>(name, _normalizeValue(value)));
       }
     }
   });
+
   return pairs;
 }
 
@@ -97,7 +97,7 @@ class _Pair<A, B> {
   final A first;
   final B second;
 
-  _Pair(this.first, this.second);
+  const _Pair(this.first, this.second);
 
   @override
   String toString() => '$first=$second';
diff --git a/chopper/pubspec.yaml b/chopper/pubspec.yaml
index 9818fc66..96817bb9 100644
--- a/chopper/pubspec.yaml
+++ b/chopper/pubspec.yaml
@@ -1,11 +1,11 @@
 name: chopper
 description: Chopper is an http client generator using source_gen, inspired by Retrofit
-version: 4.0.6
+version: 5.0.0
 documentation: https://hadrien-lejard.gitbook.io/chopper
 repository: https://github.com/lejard-h/chopper
 
 environment:
-  sdk: ">=2.12.0 <3.0.0"
+  sdk: ">=2.17.0 <3.0.0"
 
 dependencies:
   http: ">=0.13.0 <1.0.0"
@@ -18,6 +18,7 @@ dev_dependencies:
   build_test: ^2.0.0
   coverage: ^1.0.2
   http_parser: ^4.0.0
-  pedantic: ^1.11.0
+  dart_code_metrics: ^4.8.1
+  lints: ^2.0.0
   chopper_generator:
     path: ../chopper_generator
diff --git a/chopper/test/base_test.dart b/chopper/test/base_test.dart
index b591168a..99d81231 100644
--- a/chopper/test/base_test.dart
+++ b/chopper/test/base_test.dart
@@ -2,16 +2,19 @@ import 'dart:async';
 import 'dart:convert';
 
 import 'package:chopper/chopper.dart';
-import 'package:test/test.dart';
-import 'package:http/testing.dart';
 import 'package:http/http.dart' as http;
+import 'package:http/testing.dart';
+import 'package:test/test.dart';
+
 import 'test_service.dart';
 
 const baseUrl = 'http://localhost:8000';
 
 void main() {
-  final buildClient = (
-          [http.Client? httpClient, ErrorConverter? errorConverter]) =>
+  ChopperClient buildClient([
+    http.Client? httpClient,
+    ErrorConverter? errorConverter,
+  ]) =>
       ChopperClient(
         baseUrl: baseUrl,
         services: [
@@ -21,6 +24,7 @@ void main() {
         client: httpClient,
         errorConverter: errorConverter,
       );
+
   group('Base', () {
     test('get service errors', () async {
       final chopper = ChopperClient(
@@ -39,8 +43,10 @@ void main() {
       try {
         chopper.getService();
       } on Exception catch (e) {
-        expect(e.toString(),
-            'Exception: Service type should be provided, `dynamic` is not allowed.');
+        expect(
+          e.toString(),
+          'Exception: Service type should be provided, `dynamic` is not allowed.',
+        );
       }
     });
     test('GET', () async {
@@ -332,6 +338,7 @@ void main() {
       final client = MockClient((http.Request req) async {
         expect(req.headers.containsKey('foo'), isTrue);
         expect(req.headers['foo'], equals('bar'));
+
         return http.Response('', 200);
       });
 
@@ -351,6 +358,7 @@ void main() {
       final client = MockClient((http.Request req) async {
         expect(req.headers.containsKey('test'), isTrue);
         expect(req.headers['test'], equals('42'));
+
         return http.Response('', 200);
       });
 
@@ -375,6 +383,7 @@ void main() {
           req.url.toString(),
           equals('$baseUrl/test/get/1234'),
         );
+
         return http.Response('', 200);
       });
 
@@ -392,13 +401,10 @@ void main() {
 
     test('applyHeader', () {
       final req1 = applyHeader(
-          Request(
-            'GET',
-            '/',
-            baseUrl,
-          ),
-          'foo',
-          'bar');
+        Request('GET', '/', baseUrl),
+        'foo',
+        'bar',
+      );
 
       expect(req1.headers, equals({'foo': 'bar'}));
 
@@ -565,7 +571,8 @@ void main() {
         expect(
           request.url.toString(),
           equals(
-              '$baseUrl/test/query_map?test=true&foo=bar&list=1&list=2&inner.test=42'),
+            '$baseUrl/test/query_map?test=true&foo=bar&list=1&list=2&inner.test=42',
+          ),
         );
         expect(request.method, equals('GET'));
 
@@ -591,6 +598,165 @@ void main() {
     });
   });
 
+  test('Query Map 3', () async {
+    final httpClient = MockClient((request) async {
+      expect(
+        request.url.toString(),
+        equals('$baseUrl/test/query_map?name=foo&number=1234'),
+      );
+      expect(request.method, equals('GET'));
+
+      return http.Response('get response', 200);
+    });
+
+    final chopper = buildClient(httpClient);
+    final service = chopper.getService<HttpTestService>();
+
+    final response = await service.getQueryMapTest3(
+      name: 'foo',
+      number: 1234,
+    );
+
+    expect(response.body, equals('get response'));
+    expect(response.statusCode, equals(200));
+
+    httpClient.close();
+  });
+
+  test('Query Map 4 without QueryMap', () async {
+    final httpClient = MockClient((request) async {
+      expect(
+        request.url.toString(),
+        equals('$baseUrl/test/query_map?name=foo&number=1234'),
+      );
+      expect(request.method, equals('GET'));
+
+      return http.Response('get response', 200);
+    });
+
+    final chopper = buildClient(httpClient);
+    final service = chopper.getService<HttpTestService>();
+
+    final response = await service.getQueryMapTest4(
+      name: 'foo',
+      number: 1234,
+    );
+
+    expect(response.body, equals('get response'));
+    expect(response.statusCode, equals(200));
+
+    httpClient.close();
+  });
+
+  test('Query Map 4 with QueryMap', () async {
+    final httpClient = MockClient((request) async {
+      expect(
+        request.url.toString(),
+        equals(
+          '$baseUrl/test/query_map?name=foo&number=1234&filter_1=filter_value_1',
+        ),
+      );
+      expect(request.method, equals('GET'));
+
+      return http.Response('get response', 200);
+    });
+
+    final chopper = buildClient(httpClient);
+    final service = chopper.getService<HttpTestService>();
+
+    final response = await service.getQueryMapTest4(
+      name: 'foo',
+      number: 1234,
+      filters: {
+        'filter_1': 'filter_value_1',
+      },
+    );
+
+    expect(response.body, equals('get response'));
+    expect(response.statusCode, equals(200));
+
+    httpClient.close();
+  });
+
+  test(
+    'Query Map 4 with QueryMap that overwrites a previous value from Query',
+    () async {
+      final httpClient = MockClient((request) async {
+        expect(
+          request.url.toString(),
+          equals('$baseUrl/test/query_map?name=bar&number=1234'),
+        );
+        expect(request.method, equals('GET'));
+
+        return http.Response('get response', 200);
+      });
+
+      final chopper = buildClient(httpClient);
+      final service = chopper.getService<HttpTestService>();
+
+      final response = await service.getQueryMapTest4(
+        name: 'foo',
+        number: 1234,
+        filters: {
+          'name': 'bar',
+        },
+      );
+
+      expect(response.body, equals('get response'));
+      expect(response.statusCode, equals(200));
+
+      httpClient.close();
+    },
+  );
+
+  test('Query Map 5 without QueryMap', () async {
+    final httpClient = MockClient((request) async {
+      expect(
+        request.url.toString(),
+        equals('$baseUrl/test/query_map'),
+      );
+      expect(request.method, equals('GET'));
+
+      return http.Response('get response', 200);
+    });
+
+    final chopper = buildClient(httpClient);
+    final service = chopper.getService<HttpTestService>();
+
+    final response = await service.getQueryMapTest5();
+
+    expect(response.body, equals('get response'));
+    expect(response.statusCode, equals(200));
+
+    httpClient.close();
+  });
+
+  test('Query Map 5 with QueryMap', () async {
+    final httpClient = MockClient((request) async {
+      expect(
+        request.url.toString(),
+        equals('$baseUrl/test/query_map?filter_1=filter_value_1'),
+      );
+      expect(request.method, equals('GET'));
+
+      return http.Response('get response', 200);
+    });
+
+    final chopper = buildClient(httpClient);
+    final service = chopper.getService<HttpTestService>();
+
+    final response = await service.getQueryMapTest5(
+      filters: {
+        'filter_1': 'filter_value_1',
+      },
+    );
+
+    expect(response.body, equals('get response'));
+    expect(response.statusCode, equals(200));
+
+    httpClient.close();
+  });
+
   test('onRequest Stream', () async {
     final client = MockClient((http.Request req) async {
       return http.Response('ok', 200);
@@ -682,7 +848,7 @@ void main() {
     final chopper = buildClient(httpClient);
     final service = chopper.getService<HttpTestService>();
 
-    final _ = await service.getAll();
+    await service.getAll();
   });
 
   test('Slash in path gives a trailing slash', () async {
@@ -699,12 +865,13 @@ void main() {
     final chopper = buildClient(httpClient);
     final service = chopper.getService<HttpTestService>();
 
-    final _ = await service.getAllWithTrailingSlash();
+    await service.getAllWithTrailingSlash();
   });
 
   test('timeout', () async {
     final httpClient = MockClient((http.Request req) async {
       await Future.delayed(const Duration(minutes: 1));
+
       return http.Response('ok', 200);
     });
 
@@ -713,10 +880,7 @@ void main() {
 
     try {
       await service
-          .getTest(
-            '1234',
-            dynamicHeader: '',
-          )
+          .getTest('1234', dynamicHeader: '')
           .timeout(const Duration(seconds: 3));
     } catch (e) {
       expect(e is TimeoutException, isTrue);
diff --git a/chopper/test/client_test.dart b/chopper/test/client_test.dart
index 81c6d0c8..babb172d 100644
--- a/chopper/test/client_test.dart
+++ b/chopper/test/client_test.dart
@@ -1,14 +1,14 @@
 import 'dart:convert';
 
 import 'package:chopper/chopper.dart';
-import 'package:test/test.dart';
-import 'package:http/testing.dart';
 import 'package:http/http.dart' as http;
+import 'package:http/testing.dart';
+import 'package:test/test.dart';
 
 const baseUrl = 'http://localhost:8000';
 
 void main() {
-  final buildClient = ([http.Client? httpClient]) => ChopperClient(
+  ChopperClient buildClient([http.Client? httpClient]) => ChopperClient(
         baseUrl: baseUrl,
         client: httpClient,
         interceptors: [
@@ -16,6 +16,7 @@ void main() {
         ],
         converter: JsonConverter(),
       );
+
   group('Client methods', () {
     test('GET', () async {
       final httpClient = MockClient((request) async {
diff --git a/chopper/test/converter_test.dart b/chopper/test/converter_test.dart
index 7bc98b58..2fae6736 100644
--- a/chopper/test/converter_test.dart
+++ b/chopper/test/converter_test.dart
@@ -1,16 +1,17 @@
 import 'dart:convert' as dart_convert;
 
 import 'package:chopper/chopper.dart';
-import 'package:test/test.dart';
-import 'package:http/testing.dart';
 import 'package:http/http.dart' as http;
+import 'package:http/testing.dart';
+import 'package:test/test.dart';
+
 import 'test_service.dart';
 
 const baseUrl = 'http://localhost:8000';
 
 void main() {
   group('Converter', () {
-    final buildClient = (http.BaseClient client) => ChopperClient(
+    ChopperClient buildClient(http.BaseClient client) => ChopperClient(
           baseUrl: baseUrl,
           client: client,
           converter: TestConverter(),
@@ -67,39 +68,41 @@ void main() {
   group('JsonConverter', () {
     final jsonConverter = JsonConverter();
 
-    test('decode String', () {
+    test('decode String', () async {
       final value = 'foo';
       final res = Response(http.Response('"$value"', 200), '"$value"');
-      final converted = jsonConverter.convertResponse<String, String>(res);
+      final converted =
+          await jsonConverter.convertResponse<String, String>(res);
 
       expect(converted.body, equals(value));
     });
 
-    test('decode List String', () {
+    test('decode List String', () async {
       final res = Response(
         http.Response('["foo","bar"]', 200),
         '["foo","bar"]',
       );
       final converted =
-          jsonConverter.convertResponse<List<String>, String>(res);
+          await jsonConverter.convertResponse<List<String>, String>(res);
 
       expect(converted.body, equals(['foo', 'bar']));
     });
 
-    test('decode List int', () {
+    test('decode List int', () async {
       final res = Response(http.Response('[1,2]', 200), '[1,2]');
-      final converted = jsonConverter.convertResponse<List<int>, int>(res);
+      final converted =
+          await jsonConverter.convertResponse<List<int>, int>(res);
 
       expect(converted.body, equals([1, 2]));
     });
 
-    test('decode Map', () {
+    test('decode Map', () async {
       final res = Response(
         http.Response('{"foo":"bar"}', 200),
         '{"foo":"bar"}',
       );
       final converted =
-          jsonConverter.convertResponse<Map<String, String>, String>(res);
+          await jsonConverter.convertResponse<Map<String, String>, String>(res);
 
       expect(converted.body, equals({'foo': 'bar'}));
     });
@@ -111,16 +114,16 @@ class TestConverter implements Converter {
   Response<T> convertResponse<T, V>(Response res) {
     if (res.body is String) {
       return res.copyWith<_Converted<String>>(
-          body: _Converted<String>(res.body)) as Response<T>;
+        body: _Converted<String>(res.body),
+      ) as Response<T>;
     }
+
     return res as Response<T>;
   }
 
   @override
-  Request convertRequest(Request req) {
-    if (req.body is _Converted) return req.copyWith(body: req.body.data);
-    return req;
-  }
+  Request convertRequest(Request req) =>
+      req.body is _Converted ? req.copyWith(body: req.body.data) : req;
 }
 
 class TestErrorConverter implements ErrorConverter {
@@ -128,8 +131,10 @@ class TestErrorConverter implements ErrorConverter {
   Response convertError<T, V>(Response res) {
     if (res.body is String) {
       final error = dart_convert.jsonDecode(res.body);
+
       return res.copyWith<_ConvertedError>(body: _ConvertedError(error));
     }
+
     return res;
   }
 }
diff --git a/chopper/test/form_test.dart b/chopper/test/form_test.dart
index 95045d0f..ef5859d1 100644
--- a/chopper/test/form_test.dart
+++ b/chopper/test/form_test.dart
@@ -1,20 +1,21 @@
-import 'package:test/test.dart';
 import 'package:chopper/chopper.dart';
-import 'test_service.dart';
-import 'package:http/testing.dart';
 import 'package:http/http.dart' as http;
+import 'package:http/testing.dart';
+import 'package:test/test.dart';
+
+import 'test_service.dart';
 
 void main() {
   group('Form', () {
-    final buildClient =
-        (http.Client httpClient, {bool isJson = false}) => ChopperClient(
-              services: [
-                // the generated service
-                HttpTestService.create(),
-              ],
-              client: httpClient,
-              converter: isJson ? JsonConverter() : null,
-            );
+    ChopperClient buildClient(http.Client httpClient, {bool isJson = false}) =>
+        ChopperClient(
+          services: [
+            // the generated service
+            HttpTestService.create(),
+          ],
+          client: httpClient,
+          converter: isJson ? JsonConverter() : null,
+        );
 
     test('form-urlencoded default if no converter', () async {
       final httpClient = MockClient((http.Request req) async {
@@ -24,6 +25,7 @@ void main() {
           'application/x-www-form-urlencoded; charset=utf-8',
         );
         expect(req.body, 'foo=test&default=hello');
+
         return http.Response('ok', 200);
       });
 
@@ -46,6 +48,7 @@ void main() {
           'application/x-www-form-urlencoded; charset=utf-8',
         );
         expect(req.body, 'foo=test&factory=converter');
+
         return http.Response('ok', 200);
       });
 
@@ -68,6 +71,7 @@ void main() {
           'application/x-www-form-urlencoded; charset=utf-8',
         );
         expect(req.body, 'foo=test&factory=converter');
+
         return http.Response('ok', 200);
       });
 
@@ -91,6 +95,7 @@ void main() {
           'application/x-www-form-urlencoded; charset=utf-8',
         );
         expect(req.body, 'foo=test&bar=42');
+
         return http.Response('ok', 200);
       });
 
diff --git a/chopper/test/interceptors_test.dart b/chopper/test/interceptors_test.dart
index a325faeb..4650d89c 100644
--- a/chopper/test/interceptors_test.dart
+++ b/chopper/test/interceptors_test.dart
@@ -1,9 +1,10 @@
 import 'dart:async';
 
-import 'package:http/testing.dart';
+import 'package:chopper/chopper.dart';
 import 'package:http/http.dart' as http;
+import 'package:http/testing.dart';
 import 'package:test/test.dart';
-import 'package:chopper/chopper.dart';
+
 import 'test_service.dart';
 
 void main() {
@@ -14,6 +15,7 @@ void main() {
           request.url.toString(),
           equals('/test/get/1234/intercept'),
         );
+
         return http.Response('', 200);
       },
     );
@@ -78,12 +80,13 @@ void main() {
     });
 
     test('ResponseInterceptorFunc', () async {
-      var intercepted;
+      dynamic intercepted;
 
       final chopper = ChopperClient(
         interceptors: [
           (Response response) {
             intercepted = _Intercepted(response.body);
+
             return response;
           },
         ],
@@ -102,12 +105,13 @@ void main() {
     });
 
     test('TypedResponseInterceptorFunc1', () async {
-      var intercepted;
+      dynamic intercepted;
 
       final chopper = ChopperClient(
         interceptors: [
           <BodyType>(Response<BodyType> response) {
             intercepted = _Intercepted(response.body);
+
             return response;
           },
         ],
@@ -130,7 +134,7 @@ void main() {
         return http.Response('["1","2"]', 200);
       });
 
-      var intercepted;
+      dynamic intercepted;
 
       final chopper = ChopperClient(
         client: client,
@@ -139,7 +143,8 @@ void main() {
           <BodyType, InnerType>(Response<BodyType> response) {
             expect(isTypeOf<String, InnerType>(), isTrue);
             expect(isTypeOf<BodyType, List<String>>(), isTrue);
-            intercepted = _Intercepted<BodyType>(response.body!);
+            intercepted = _Intercepted<BodyType>(response.body as BodyType);
+
             return response;
           },
         ],
@@ -157,12 +162,13 @@ void main() {
       final client = MockClient((http.Request req) async {
         expect(req.headers.containsKey('foo'), isTrue);
         expect(req.headers['foo'], equals('bar'));
+
         return http.Response('', 200);
       });
 
       final chopper = ChopperClient(
         interceptors: [
-          HeadersInterceptor({'foo': 'bar'})
+          HeadersInterceptor({'foo': 'bar'}),
         ],
         services: [
           HttpTestService.create(),
@@ -223,9 +229,12 @@ void main() {
       final logger = HttpLoggingInterceptor();
 
       final fakeResponse = Response<String>(
-        http.Response('responseBodyBase', 200,
-            headers: {'foo': 'bar'},
-            request: await fakeRequest.toBaseRequest()),
+        http.Response(
+          'responseBodyBase',
+          200,
+          headers: {'foo': 'bar'},
+          request: await fakeRequest.toBaseRequest(),
+        ),
         'responseBody',
       );
 
@@ -254,6 +263,7 @@ class ResponseIntercept implements ResponseInterceptor {
   @override
   FutureOr<Response> onResponse(Response response) {
     intercepted = _Intercepted(response.body);
+
     return response;
   }
 }
diff --git a/chopper/test/json_test.dart b/chopper/test/json_test.dart
index c65053f0..6a8c637f 100644
--- a/chopper/test/json_test.dart
+++ b/chopper/test/json_test.dart
@@ -1,10 +1,11 @@
 import 'dart:convert';
 
-import 'package:test/test.dart';
 import 'package:chopper/chopper.dart';
-import 'test_service.dart';
-import 'package:http/testing.dart';
 import 'package:http/http.dart' as http;
+import 'package:http/testing.dart';
+import 'package:test/test.dart';
+
+import 'test_service.dart';
 
 void main() {
   final sample = {
@@ -15,7 +16,8 @@ void main() {
     'result': 'ok',
   };
   group('JSON', () {
-    final buildClient = (bool json, http.Client httpClient) => ChopperClient(
+    ChopperClient buildClient(bool json, http.Client httpClient) =>
+        ChopperClient(
           services: [
             // the generated service
             HttpTestService.create(),
@@ -30,6 +32,7 @@ void main() {
         expect(req.url.toString(), equals('/test/map'));
         expect(req.headers['content-type'], 'application/json; charset=utf-8');
         expect(req.body, equals(json.encode(sample)));
+
         return http.Response(
           json.encode(res),
           200,
@@ -56,6 +59,7 @@ void main() {
         expect(req.headers['content-type'], 'application/json; charset=utf-8');
         expect(req.headers['customConverter'], 'true');
         expect(req.body, equals(json.encode(sample)));
+
         return http.Response(
           json.encode(res),
           200,
diff --git a/chopper/test/multipart_test.dart b/chopper/test/multipart_test.dart
index ca42cd95..20d28044 100644
--- a/chopper/test/multipart_test.dart
+++ b/chopper/test/multipart_test.dart
@@ -1,8 +1,9 @@
 import 'package:chopper/chopper.dart';
+import 'package:http/http.dart' as http;
+import 'package:http/testing.dart';
 import 'package:http_parser/http_parser.dart';
 import 'package:test/test.dart';
-import 'package:http/testing.dart';
-import 'package:http/http.dart' as http;
+
 import 'test_service.dart';
 
 void main() {
@@ -26,6 +27,7 @@ void main() {
             '{bar: foo}\r\n',
           ),
         );
+
         return http.Response('ok', 200);
       });
 
@@ -46,14 +48,14 @@ void main() {
           contains('content-type: application/octet-stream'),
         );
         expect(
-            req.body,
-            contains(
-              'content-disposition: form-data; name="file"',
-            ));
+          req.body,
+          contains('content-disposition: form-data; name="file"'),
+        );
         expect(
           req.body,
-          contains('${String.fromCharCodes([0, 1, 2, 3, 4, 5, 6, 7, 8, 9])}'),
+          contains(String.fromCharCodes([0, 1, 2, 3, 4, 5, 6, 7, 8, 9])),
         );
+
         return http.Response('ok', 200);
       });
 
@@ -79,14 +81,16 @@ void main() {
         isNot(contains('content-disposition: form-data; name="id"')),
       );
       expect(
-          req.body,
-          contains(
-            'content-disposition: form-data; name="file_field"; filename="file_name"',
-          ));
+        req.body,
+        contains(
+          'content-disposition: form-data; name="file_field"; filename="file_name"',
+        ),
+      );
       expect(
         req.body,
-        contains('${String.fromCharCodes([0, 1, 2, 3, 4, 5, 6, 7, 8, 9])}'),
+        contains(String.fromCharCodes([0, 1, 2, 3, 4, 5, 6, 7, 8, 9])),
       );
+
       return http.Response('ok', 200);
     });
 
@@ -109,22 +113,28 @@ void main() {
     final httpClient = MockClient((http.Request req) async {
       expect(req.headers['Content-Type'], contains('multipart/form-data;'));
 
-      expect(req.body,
-          contains('content-disposition: form-data; name="id"\r\n\r\n42\r\n'));
+      expect(
+        req.body,
+        contains(
+          'content-disposition: form-data; name="id"\r\n\r\n42\r\n',
+        ),
+      );
 
       expect(
         req.body,
         contains('content-type: application/octet-stream'),
       );
       expect(
-          req.body,
-          contains(
-            'content-disposition: form-data; name="file_field"; filename="file_name"',
-          ));
+        req.body,
+        contains(
+          'content-disposition: form-data; name="file_field"; filename="file_name"',
+        ),
+      );
       expect(
         req.body,
-        contains('${String.fromCharCodes([0, 1, 2, 3, 4, 5, 6, 7, 8, 9])}'),
+        contains(String.fromCharCodes([0, 1, 2, 3, 4, 5, 6, 7, 8, 9])),
       );
+
       return http.Response('ok', 200);
     });
 
@@ -166,6 +176,7 @@ void main() {
           'World',
         ),
       );
+
       return http.Response('ok', 200);
     });
 
@@ -206,23 +217,29 @@ void main() {
     expect(req.fields['int'], equals('42'));
   });
 
-  test('PartFile', () async {
-    final req = await toMultipartRequest(
-      [
-        PartValueFile<String>('foo', 'test/multipart_test.dart'),
-        PartValueFile<List<int>>('int', [1, 2]),
-      ],
-      HttpMethod.Post,
-      Uri.parse('/foo'),
-      {},
-    );
+  test(
+    'PartFile',
+    () async {
+      final req = await toMultipartRequest(
+        [
+          PartValueFile<String>('foo', 'test/multipart_test.dart'),
+          PartValueFile<List<int>>('int', [1, 2]),
+        ],
+        HttpMethod.Post,
+        Uri.parse('/foo'),
+        {},
+      );
 
-    expect(req.files.firstWhere((f) => f.field == 'foo').filename,
-        equals('multipart_test.dart'));
-    final bytes =
-        await req.files.firstWhere((f) => f.field == 'int').finalize().first;
-    expect(bytes, equals([1, 2]));
-  }, testOn: 'vm');
+      expect(
+        req.files.firstWhere((f) => f.field == 'foo').filename,
+        equals('multipart_test.dart'),
+      );
+      final bytes =
+          await req.files.firstWhere((f) => f.field == 'int').finalize().first;
+      expect(bytes, equals([1, 2]));
+    },
+    testOn: 'vm',
+  );
 
   test('PartValue.replace', () {
     dynamic part = PartValue<String>('foo', 'bar');
diff --git a/chopper/test/test_service.chopper.dart b/chopper/test/test_service.chopper.dart
index 2d03d152..f1fd6769 100644
--- a/chopper/test/test_service.chopper.dart
+++ b/chopper/test/test_service.chopper.dart
@@ -6,7 +6,7 @@ part of 'test_service.dart';
 // ChopperGenerator
 // **************************************************************************
 
-// ignore_for_file: always_put_control_body_on_new_line, always_specify_types, prefer_const_declarations
+// ignore_for_file: always_put_control_body_on_new_line, always_specify_types, prefer_const_declarations, unnecessary_brace_in_string_interps
 class _$HttpTestService extends HttpTestService {
   _$HttpTestService([ChopperClient? client]) {
     if (client == null) return;
@@ -18,7 +18,7 @@ class _$HttpTestService extends HttpTestService {
 
   @override
   Future<Response<String>> getTest(String id, {required String dynamicHeader}) {
-    final $url = '/test/get/$id';
+    final $url = '/test/get/${id}';
     final $headers = {
       'test': dynamicHeader,
     };
@@ -93,6 +93,36 @@ class _$HttpTestService extends HttpTestService {
     return client.send<dynamic, dynamic>($request);
   }
 
+  @override
+  Future<Response<dynamic>> getQueryMapTest3(
+      {String name = '',
+      int? number,
+      Map<String, dynamic> filters = const {}}) {
+    final $url = '/test/query_map';
+    final $params = <String, dynamic>{'name': name, 'number': number};
+    $params.addAll(filters);
+    final $request = Request('GET', $url, client.baseUrl, parameters: $params);
+    return client.send<dynamic, dynamic>($request);
+  }
+
+  @override
+  Future<Response<dynamic>> getQueryMapTest4(
+      {String name = '', int? number, Map<String, dynamic>? filters}) {
+    final $url = '/test/query_map';
+    final $params = <String, dynamic>{'name': name, 'number': number};
+    $params.addAll(filters ?? {});
+    final $request = Request('GET', $url, client.baseUrl, parameters: $params);
+    return client.send<dynamic, dynamic>($request);
+  }
+
+  @override
+  Future<Response<dynamic>> getQueryMapTest5({Map<String, dynamic>? filters}) {
+    final $url = '/test/query_map';
+    final $params = filters ?? {};
+    final $request = Request('GET', $url, client.baseUrl, parameters: $params);
+    return client.send<dynamic, dynamic>($request);
+  }
+
   @override
   Future<Response<dynamic>> getBody(dynamic body) {
     final $url = '/test/get_body';
@@ -119,7 +149,7 @@ class _$HttpTestService extends HttpTestService {
 
   @override
   Future<Response<dynamic>> putTest(String test, String data) {
-    final $url = '/test/put/$test';
+    final $url = '/test/put/${test}';
     final $body = data;
     final $request = Request('PUT', $url, client.baseUrl, body: $body);
     return client.send<dynamic, dynamic>($request);
@@ -127,7 +157,7 @@ class _$HttpTestService extends HttpTestService {
 
   @override
   Future<Response<dynamic>> deleteTest(String id) {
-    final $url = '/test/delete/$id';
+    final $url = '/test/delete/${id}';
     final $headers = {
       'foo': 'bar',
     };
@@ -138,7 +168,7 @@ class _$HttpTestService extends HttpTestService {
 
   @override
   Future<Response<dynamic>> patchTest(String id, String data) {
-    final $url = '/test/patch/$id';
+    final $url = '/test/patch/${id}';
     final $body = data;
     final $request = Request('PATCH', $url, client.baseUrl, body: $body);
     return client.send<dynamic, dynamic>($request);
diff --git a/chopper/test/test_service.dart b/chopper/test/test_service.dart
index 1c68866a..03abc239 100644
--- a/chopper/test/test_service.dart
+++ b/chopper/test/test_service.dart
@@ -1,7 +1,7 @@
 import 'dart:async';
 import 'dart:convert';
-import 'package:chopper/chopper.dart';
 
+import 'package:chopper/chopper.dart';
 import 'package:http/http.dart' show MultipartFile;
 
 part 'test_service.chopper.dart';
@@ -48,6 +48,25 @@ abstract class HttpTestService extends ChopperService {
     @Query('test') bool? test,
   });
 
+  @Get(path: 'query_map')
+  Future<Response> getQueryMapTest3({
+    @Query('name') String name = '',
+    @Query('number') int? number,
+    @QueryMap() Map<String, dynamic> filters = const {},
+  });
+
+  @Get(path: 'query_map')
+  Future<Response> getQueryMapTest4({
+    @Query('name') String name = '',
+    @Query('number') int? number,
+    @QueryMap() Map<String, dynamic>? filters,
+  });
+
+  @Get(path: 'query_map')
+  Future<Response> getQueryMapTest5({
+    @QueryMap() Map<String, dynamic>? filters,
+  });
+
   @Get(path: 'get_body')
   Future<Response> getBody(@Body() dynamic body);
 
@@ -82,7 +101,9 @@ abstract class HttpTestService extends ChopperService {
 
   @Post(path: 'map/json')
   @FactoryConverter(
-      request: customConvertRequest, response: customConvertResponse)
+    request: customConvertRequest,
+    response: customConvertResponse,
+  )
   Future<Response> forceJsonTest(@Body() Map map);
 
   @Post(path: 'multi')
@@ -121,6 +142,7 @@ abstract class HttpTestService extends ChopperService {
 
 Request customConvertRequest(Request req) {
   final r = JsonConverter().convertRequest(req);
+
   return applyHeader(r, 'customConverter', 'true');
 }
 
diff --git a/chopper_built_value/CHANGELOG.md b/chopper_built_value/CHANGELOG.md
index df5a3b34..e3a476bc 100644
--- a/chopper_built_value/CHANGELOG.md
+++ b/chopper_built_value/CHANGELOG.md
@@ -1,5 +1,9 @@
 # Changelog
 
+## 1.1.0
+
+- Chopper upgraded
+
 ## 1.0.0
 
 - Null safety support
diff --git a/chopper_built_value/analysis_options.yaml b/chopper_built_value/analysis_options.yaml
index d4fcc1ad..7f5a674f 100644
--- a/chopper_built_value/analysis_options.yaml
+++ b/chopper_built_value/analysis_options.yaml
@@ -1 +1,34 @@
-include: package:pedantic/analysis_options.yaml
\ No newline at end of file
+include: package:lints/recommended.yaml
+
+analyzer:
+  exclude:
+    - "**.g.dart"
+    - "**.chopper.dart"
+    - "**.mocks.dart"
+    - "example/**"
+  plugins:
+    - dart_code_metrics
+
+dart_code_metrics:
+  metrics:
+    cyclomatic-complexity: 20
+    number-of-arguments: 4
+    maximum-nesting-level: 5
+    number-of-parameters: 7
+  metrics-exclude:
+    - test/**
+  rules:
+    - newline-before-return
+    - no-boolean-literal-compare
+    - no-empty-block
+    - prefer-trailing-comma
+    - prefer-conditional-expressions
+    - no-equal-then-else
+  anti-patterns:
+    - long-method
+    - long-parameter-list
+
+linter:
+  rules:
+    avoid_print: true
+    prefer_single_quotes: true
diff --git a/chopper_built_value/lib/chopper_built_value.dart b/chopper_built_value/lib/chopper_built_value.dart
index 0468d0a0..7beef449 100644
--- a/chopper_built_value/lib/chopper_built_value.dart
+++ b/chopper_built_value/lib/chopper_built_value.dart
@@ -1,13 +1,14 @@
-import 'package:chopper/chopper.dart';
+import 'dart:async';
 
 import 'package:built_collection/built_collection.dart';
 import 'package:built_value/serializer.dart';
+import 'package:chopper/chopper.dart';
 
 /// A custom [Converter] and [ErrorConverter] that handles conversion for classes
 /// having a serializer implementation made with the built_value package.
 class BuiltValueConverter implements Converter, ErrorConverter {
   final Serializers serializers;
-  final JsonConverter jsonConverter = JsonConverter();
+  static const JsonConverter jsonConverter = JsonConverter();
   final Type? errorType;
 
   /// Builds a new BuiltValueConverter instance that uses built_value serializers defined
@@ -16,10 +17,10 @@ class BuiltValueConverter implements Converter, ErrorConverter {
   /// If the error body cannot be converted with serializers and [errorType] is provided
   /// and it's not `null`, BuiltValueConverter will try to deserialize the error body into
   /// [errorType].
-  BuiltValueConverter(this.serializers, {this.errorType});
+  const BuiltValueConverter(this.serializers, {this.errorType});
 
   T? _deserialize<T>(dynamic value) {
-    var serializer;
+    dynamic serializer;
     if (value is Map && value.containsKey('\$')) {
       serializer = serializers.serializerForWireName(value['\$']);
     }
@@ -33,7 +34,9 @@ class BuiltValueConverter implements Converter, ErrorConverter {
   }
 
   BuiltList<InnerType> _deserializeListOf<InnerType>(Iterable value) {
-    final deserialized = value.map((value) => _deserialize<InnerType>(value));
+    final Iterable<InnerType?> deserialized =
+        value.map((value) => _deserialize<InnerType>(value));
+
     return BuiltList<InnerType>(deserialized.toList(growable: false));
   }
 
@@ -42,27 +45,33 @@ class BuiltValueConverter implements Converter, ErrorConverter {
     if (entity is Iterable) {
       return _deserializeListOf<InnerType>(entity) as BodyType;
     }
+
     return _deserialize<BodyType>(entity);
   }
 
   @override
-  Request convertRequest(Request request) {
-    request = request.copyWith(body: serializers.serialize(request.body));
-    return jsonConverter.convertRequest(request);
-  }
+  Request convertRequest(Request request) => jsonConverter.convertRequest(
+        request.copyWith(body: serializers.serialize(request.body)),
+      );
 
   @override
-  Response<BodyType> convertResponse<BodyType, InnerType>(Response response) {
-    final jsonResponse = jsonConverter.convertResponse(response);
-    final body = deserialize<BodyType, InnerType>(jsonResponse.body);
-    return jsonResponse.copyWith(body: body);
+  FutureOr<Response<BodyType>> convertResponse<BodyType, InnerType>(
+    Response response,
+  ) async {
+    final Response jsonResponse = await jsonConverter.convertResponse(response);
+
+    return jsonResponse.copyWith(
+      body: deserialize<BodyType, InnerType>(jsonResponse.body),
+    );
   }
 
   @override
-  Response convertError<BodyType, InnerType>(Response response) {
-    final jsonResponse = jsonConverter.convertResponse(response);
+  FutureOr<Response> convertError<BodyType, InnerType>(
+    Response response,
+  ) async {
+    final Response jsonResponse = await jsonConverter.convertResponse(response);
 
-    var body;
+    dynamic body;
 
     try {
       // try to deserialize using wireName
diff --git a/chopper_built_value/pubspec.yaml b/chopper_built_value/pubspec.yaml
index 88ccd7fc..0bd63c23 100644
--- a/chopper_built_value/pubspec.yaml
+++ b/chopper_built_value/pubspec.yaml
@@ -1,16 +1,16 @@
 name: chopper_built_value
 description: A built_value based Converter for Chopper.
-version: 1.0.0
+version: 1.1.0
 documentation: https://hadrien-lejard.gitbook.io/chopper/converters/built-value-converter
 repository: https://github.com/lejard-h/chopper
 
 environment:
-  sdk: ">=2.12.0 <3.0.0"
+  sdk: ">=2.17.0 <3.0.0"
 
 dependencies:
   built_value: ^8.0.0
   built_collection: ^5.0.0
-  chopper: ^4.0.0
+  chopper: ^5.0.0
   http: ^0.13.0
 
 dev_dependencies:
@@ -18,7 +18,8 @@ dev_dependencies:
   build_runner: ^2.0.0
   build_test: ^2.0.0
   built_value_generator: ^8.0.6
-  pedantic: ^1.10.0
+  dart_code_metrics: ^4.8.1
+  lints: ^2.0.0
 
 dependency_overrides:
   # Comment before publish
diff --git a/chopper_built_value/test/converter_test.dart b/chopper_built_value/test/converter_test.dart
index f16b4171..2766f645 100644
--- a/chopper_built_value/test/converter_test.dart
+++ b/chopper_built_value/test/converter_test.dart
@@ -2,8 +2,8 @@ import 'package:built_collection/built_collection.dart';
 import 'package:built_value/standard_json_plugin.dart';
 import 'package:chopper/chopper.dart';
 import 'package:chopper_built_value/chopper_built_value.dart';
-import 'package:test/test.dart';
 import 'package:http/http.dart' as http;
+import 'package:test/test.dart';
 
 import 'data.dart';
 import 'serializers.dart';
@@ -31,31 +31,31 @@ void main() {
       expect(request.body, '{"\$":"DataModel","id":42,"name":"foo"}');
     });
 
-    test('convert response with wireName', () {
+    test('convert response with wireName', () async {
       final string = '{"\$":"DataModel","id":42,"name":"foo"}';
       final response = Response(http.Response(string, 200), string);
       final convertedResponse =
-          converter.convertResponse<DataModel, DataModel>(response);
+          await converter.convertResponse<DataModel, DataModel>(response);
 
       expect(convertedResponse.body?.id, equals(42));
       expect(convertedResponse.body?.name, equals('foo'));
     });
 
-    test('convert response without wireName', () {
+    test('convert response without wireName', () async {
       final string = '{"id":42,"name":"foo"}';
       final response = Response(http.Response(string, 200), string);
       final convertedResponse =
-          converter.convertResponse<DataModel, DataModel>(response);
+          await converter.convertResponse<DataModel, DataModel>(response);
 
       expect(convertedResponse.body?.id, equals(42));
       expect(convertedResponse.body?.name, equals('foo'));
     });
 
-    test('convert response List', () {
+    test('convert response List', () async {
       final string = '[{"id":42,"name":"foo"},{"id":25,"name":"bar"}]';
       final response = Response(http.Response(string, 200), string);
-      final convertedResponse =
-          converter.convertResponse<BuiltList<DataModel>, DataModel>(response);
+      final convertedResponse = await converter
+          .convertResponse<BuiltList<DataModel>, DataModel>(response);
 
       final list = convertedResponse.body;
       expect(list?.first.id, equals(42));
@@ -71,19 +71,19 @@ void main() {
       expect(request.headers['content-type'], equals('application/json'));
     });
 
-    test('convert error with wire name', () {
+    test('convert error with wire name', () async {
       final string = '{"\$":"DataModel","id":42,"name":"foo"}';
       final response = Response(http.Response(string, 200), string);
-      final convertedResponse = converter.convertError(response);
+      final convertedResponse = await converter.convertError(response);
 
       expect(convertedResponse.body.id, equals(42));
       expect(convertedResponse.body.name, equals('foo'));
     });
 
-    test('convert error using provided type', () {
+    test('convert error using provided type', () async {
       final string = '{"message":"Error message"}';
       final response = Response(http.Response(string, 200), string);
-      final convertedResponse = converter.convertError(response);
+      final convertedResponse = await converter.convertError(response);
 
       expect(convertedResponse.body.message, equals('Error message'));
     });
diff --git a/chopper_built_value/test/data.g.dart b/chopper_built_value/test/data.g.dart
index df30695c..d9413768 100644
--- a/chopper_built_value/test/data.g.dart
+++ b/chopper_built_value/test/data.g.dart
@@ -35,17 +35,17 @@ class _$DataModelSerializer implements StructuredSerializer<DataModel> {
 
     final iterator = serialized.iterator;
     while (iterator.moveNext()) {
-      final key = iterator.current as String;
+      final key = iterator.current! as String;
       iterator.moveNext();
       final Object? value = iterator.current;
       switch (key) {
         case 'id':
           result.id = serializers.deserialize(value,
-              specifiedType: const FullType(int)) as int;
+              specifiedType: const FullType(int))! as int;
           break;
         case 'name':
           result.name = serializers.deserialize(value,
-              specifiedType: const FullType(String)) as String;
+              specifiedType: const FullType(String))! as String;
           break;
       }
     }
@@ -79,13 +79,13 @@ class _$ErrorModelSerializer implements StructuredSerializer<ErrorModel> {
 
     final iterator = serialized.iterator;
     while (iterator.moveNext()) {
-      final key = iterator.current as String;
+      final key = iterator.current! as String;
       iterator.moveNext();
       final Object? value = iterator.current;
       switch (key) {
         case 'message':
           result.message = serializers.deserialize(value,
-              specifiedType: const FullType(String)) as String;
+              specifiedType: const FullType(String))! as String;
           break;
       }
     }
@@ -101,11 +101,11 @@ class _$DataModel extends DataModel {
   final String name;
 
   factory _$DataModel([void Function(DataModelBuilder)? updates]) =>
-      (new DataModelBuilder()..update(updates)).build();
+      (new DataModelBuilder()..update(updates))._build();
 
   _$DataModel._({required this.id, required this.name}) : super._() {
-    BuiltValueNullFieldError.checkNotNull(id, 'DataModel', 'id');
-    BuiltValueNullFieldError.checkNotNull(name, 'DataModel', 'name');
+    BuiltValueNullFieldError.checkNotNull(id, r'DataModel', 'id');
+    BuiltValueNullFieldError.checkNotNull(name, r'DataModel', 'name');
   }
 
   @override
@@ -128,7 +128,7 @@ class _$DataModel extends DataModel {
 
   @override
   String toString() {
-    return (newBuiltValueToStringHelper('DataModel')
+    return (newBuiltValueToStringHelper(r'DataModel')
           ..add('id', id)
           ..add('name', name))
         .toString();
@@ -170,12 +170,14 @@ class DataModelBuilder implements Builder<DataModel, DataModelBuilder> {
   }
 
   @override
-  _$DataModel build() {
+  DataModel build() => _build();
+
+  _$DataModel _build() {
     final _$result = _$v ??
         new _$DataModel._(
-            id: BuiltValueNullFieldError.checkNotNull(id, 'DataModel', 'id'),
+            id: BuiltValueNullFieldError.checkNotNull(id, r'DataModel', 'id'),
             name: BuiltValueNullFieldError.checkNotNull(
-                name, 'DataModel', 'name'));
+                name, r'DataModel', 'name'));
     replace(_$result);
     return _$result;
   }
@@ -186,10 +188,10 @@ class _$ErrorModel extends ErrorModel {
   final String message;
 
   factory _$ErrorModel([void Function(ErrorModelBuilder)? updates]) =>
-      (new ErrorModelBuilder()..update(updates)).build();
+      (new ErrorModelBuilder()..update(updates))._build();
 
   _$ErrorModel._({required this.message}) : super._() {
-    BuiltValueNullFieldError.checkNotNull(message, 'ErrorModel', 'message');
+    BuiltValueNullFieldError.checkNotNull(message, r'ErrorModel', 'message');
   }
 
   @override
@@ -212,7 +214,7 @@ class _$ErrorModel extends ErrorModel {
 
   @override
   String toString() {
-    return (newBuiltValueToStringHelper('ErrorModel')..add('message', message))
+    return (newBuiltValueToStringHelper(r'ErrorModel')..add('message', message))
         .toString();
   }
 }
@@ -247,14 +249,16 @@ class ErrorModelBuilder implements Builder<ErrorModel, ErrorModelBuilder> {
   }
 
   @override
-  _$ErrorModel build() {
+  ErrorModel build() => _build();
+
+  _$ErrorModel _build() {
     final _$result = _$v ??
         new _$ErrorModel._(
             message: BuiltValueNullFieldError.checkNotNull(
-                message, 'ErrorModel', 'message'));
+                message, r'ErrorModel', 'message'));
     replace(_$result);
     return _$result;
   }
 }
 
-// ignore_for_file: always_put_control_body_on_new_line,always_specify_types,annotate_overrides,avoid_annotating_with_dynamic,avoid_as,avoid_catches_without_on_clauses,avoid_returning_this,lines_longer_than_80_chars,omit_local_variable_types,prefer_expression_function_bodies,sort_constructors_first,test_types_in_equals,unnecessary_const,unnecessary_new
+// ignore_for_file: always_put_control_body_on_new_line,always_specify_types,annotate_overrides,avoid_annotating_with_dynamic,avoid_as,avoid_catches_without_on_clauses,avoid_returning_this,deprecated_member_use_from_same_package,lines_longer_than_80_chars,no_leading_underscores_for_local_identifiers,omit_local_variable_types,prefer_expression_function_bodies,sort_constructors_first,test_types_in_equals,unnecessary_const,unnecessary_new,unnecessary_lambdas
diff --git a/chopper_built_value/test/serializers.dart b/chopper_built_value/test/serializers.dart
index 370f4b37..7124a7c1 100644
--- a/chopper_built_value/test/serializers.dart
+++ b/chopper_built_value/test/serializers.dart
@@ -1,6 +1,7 @@
 library serializers;
 
 import 'package:built_value/serializer.dart';
+
 import 'data.dart';
 
 part 'serializers.g.dart';
diff --git a/chopper_built_value/test/serializers.g.dart b/chopper_built_value/test/serializers.g.dart
index 6cb3a9e7..55d2a7d3 100644
--- a/chopper_built_value/test/serializers.g.dart
+++ b/chopper_built_value/test/serializers.g.dart
@@ -11,4 +11,4 @@ Serializers _$serializers = (new Serializers().toBuilder()
       ..add(ErrorModel.serializer))
     .build();
 
-// ignore_for_file: always_put_control_body_on_new_line,always_specify_types,annotate_overrides,avoid_annotating_with_dynamic,avoid_as,avoid_catches_without_on_clauses,avoid_returning_this,lines_longer_than_80_chars,omit_local_variable_types,prefer_expression_function_bodies,sort_constructors_first,test_types_in_equals,unnecessary_const,unnecessary_new
+// ignore_for_file: always_put_control_body_on_new_line,always_specify_types,annotate_overrides,avoid_annotating_with_dynamic,avoid_as,avoid_catches_without_on_clauses,avoid_returning_this,deprecated_member_use_from_same_package,lines_longer_than_80_chars,no_leading_underscores_for_local_identifiers,omit_local_variable_types,prefer_expression_function_bodies,sort_constructors_first,test_types_in_equals,unnecessary_const,unnecessary_new,unnecessary_lambdas
diff --git a/chopper_generator/CHANGELOG.md b/chopper_generator/CHANGELOG.md
index 3e27a067..22074e42 100644
--- a/chopper_generator/CHANGELOG.md
+++ b/chopper_generator/CHANGELOG.md
@@ -1,17 +1,12 @@
 # Changelog
 
-## 4.0.6
+## 5.0.0
 
-- Analyzer dependency upgrade
-
-## 4.0.5
-
-- Analyzer dependency upgrade
-- Fix for warnings
+- API breaking changes (FutureOr usage)
 
 ## 4.0.3
 
-- Interpolation fixes
+- Analyzer dependency upgrade
 
 ## 4.0.2
 
diff --git a/chopper_generator/analysis_options.yaml b/chopper_generator/analysis_options.yaml
index d4fcc1ad..57256269 100644
--- a/chopper_generator/analysis_options.yaml
+++ b/chopper_generator/analysis_options.yaml
@@ -1 +1,35 @@
-include: package:pedantic/analysis_options.yaml
\ No newline at end of file
+include: package:lints/recommended.yaml
+
+analyzer:
+  exclude:
+    - "**.g.dart"
+    - "**.chopper.dart"
+    - "**.mocks.dart"
+    - "example/**"
+  plugins:
+    - dart_code_metrics
+
+dart_code_metrics:
+  metrics:
+    cyclomatic-complexity: 20
+    number-of-arguments: 4
+    maximum-nesting-level: 5
+    number-of-parameters: 5
+    source-lines-of-code: 200
+  metrics-exclude:
+    - test/**
+  rules:
+    - newline-before-return
+    - no-boolean-literal-compare
+    - no-empty-block
+    - prefer-trailing-comma
+    - prefer-conditional-expressions
+    - no-equal-then-else
+  anti-patterns:
+    - long-method
+    - long-parameter-list
+
+linter:
+  rules:
+    avoid_print: true
+    prefer_single_quotes: true
diff --git a/chopper_generator/lib/chopper_generator.dart b/chopper_generator/lib/chopper_generator.dart
index 2facc8b0..74355389 100644
--- a/chopper_generator/lib/chopper_generator.dart
+++ b/chopper_generator/lib/chopper_generator.dart
@@ -1,6 +1,7 @@
 library chopper_generator.dart;
 
 import 'package:build/build.dart';
+
 import 'src/generator.dart';
 
 Builder chopperGeneratorFactory(BuilderOptions options) =>
diff --git a/chopper_generator/lib/src/generator.dart b/chopper_generator/lib/src/generator.dart
index a3ae9880..13b3c606 100644
--- a/chopper_generator/lib/src/generator.dart
+++ b/chopper_generator/lib/src/generator.dart
@@ -1,31 +1,28 @@
 ///@nodoc
 import 'dart:async';
 
+import 'package:analyzer/dart/constant/value.dart';
 import 'package:analyzer/dart/element/element.dart';
 import 'package:analyzer/dart/element/nullability_suffix.dart';
 import 'package:analyzer/dart/element/type.dart';
-
 import 'package:build/build.dart';
 import 'package:built_collection/built_collection.dart';
-import 'package:dart_style/dart_style.dart';
-
-import 'package:source_gen/source_gen.dart';
-// TODO(lejard_h) Code builder not null safe yet
-// ignore: import_of_legacy_library_into_null_safe
-import 'package:code_builder/code_builder.dart';
 import 'package:chopper/chopper.dart' as chopper;
+import 'package:code_builder/code_builder.dart';
+import 'package:dart_style/dart_style.dart';
 import 'package:logging/logging.dart';
+import 'package:source_gen/source_gen.dart';
 
-const _clientVar = 'client';
-const _baseUrlVar = 'baseUrl';
-const _parametersVar = '\$params';
-const _headersVar = '\$headers';
-const _requestVar = '\$request';
-const _bodyVar = '\$body';
-const _partsVar = '\$parts';
-const _urlVar = '\$url';
+const String _clientVar = 'client';
+const String _baseUrlVar = 'baseUrl';
+const String _parametersVar = r'$params';
+const String _headersVar = r'$headers';
+const String _requestVar = r'$request';
+const String _bodyVar = r'$body';
+const String _partsVar = r'$parts';
+const String _urlVar = r'$url';
 
-final _logger = Logger('Chopper Generator');
+final Logger _logger = Logger('Chopper Generator');
 
 class ChopperGenerator extends GeneratorForAnnotation<chopper.ChopperApi> {
   @override
@@ -35,7 +32,7 @@ class ChopperGenerator extends GeneratorForAnnotation<chopper.ChopperApi> {
     BuildStep buildStep,
   ) {
     if (element is! ClassElement) {
-      final friendlyName = element.displayName;
+      final String friendlyName = element.displayName;
       throw InvalidGenerationSourceError(
         'Generator cannot target `$friendlyName`.',
         todo: 'Remove the [ChopperApi] annotation from `$friendlyName`.',
@@ -61,18 +58,18 @@ class ChopperGenerator extends GeneratorForAnnotation<chopper.ChopperApi> {
     ClassElement element,
   ) {
     if (!element.allSupertypes.any(_extendsChopperService)) {
-      final friendlyName = element.displayName;
+      final String friendlyName = element.displayName;
       throw InvalidGenerationSourceError(
         'Generator cannot target `$friendlyName`.',
         todo: '`$friendlyName` need to extends the [ChopperService] class.',
       );
     }
 
-    final friendlyName = element.name;
-    final name = '_\$$friendlyName';
-    final baseUrl = annotation.peek(_baseUrlVar)?.stringValue ?? '';
+    final String friendlyName = element.name;
+    final String name = '_\$$friendlyName';
+    final String baseUrl = annotation.peek(_baseUrlVar)?.stringValue ?? '';
 
-    final classBuilder = Class((builder) {
+    final Class classBuilder = Class((builder) {
       builder
         ..name = name
         ..extend = refer(friendlyName)
@@ -81,57 +78,70 @@ class ChopperGenerator extends GeneratorForAnnotation<chopper.ChopperApi> {
         ..methods.addAll(_parseMethods(element, baseUrl));
     });
 
-    final ignore =
+    final String ignore =
         '// ignore_for_file: always_put_control_body_on_new_line, always_specify_types, prefer_const_declarations, unnecessary_brace_in_string_interps';
-    final emitter = DartEmitter();
+    final DartEmitter emitter = DartEmitter();
+
     return DartFormatter().format('$ignore\n${classBuilder.accept(emitter)}');
   }
 
-  Constructor _generateConstructor() => Constructor((constructorBuilder) {
-        constructorBuilder.optionalParameters.add(
-          Parameter((paramBuilder) {
-            paramBuilder.name = _clientVar;
-            paramBuilder.type = refer('${chopper.ChopperClient}?');
-          }),
-        );
+  Constructor _generateConstructor() => Constructor(
+        (ConstructorBuilder constructorBuilder) {
+          constructorBuilder.optionalParameters.add(
+            Parameter((paramBuilder) {
+              paramBuilder.name = _clientVar;
+              paramBuilder.type = refer('${chopper.ChopperClient}?');
+            }),
+          );
 
-        constructorBuilder.body = Code(
-          'if ($_clientVar == null) return;\nthis.$_clientVar = $_clientVar;',
-        );
-      });
-
-  Iterable<Method> _parseMethods(ClassElement element, String baseUrl) {
-    return element.methods.where((MethodElement method) {
-      final methodAnnotation = _getMethodAnnotation(method);
-      return methodAnnotation != null &&
-          method.isAbstract &&
-          method.returnType.isDartAsyncFuture;
-    }).map((MethodElement m) => _generateMethod(m, baseUrl));
-  }
+          constructorBuilder.body = Code(
+            'if ($_clientVar == null) return;\nthis.$_clientVar = $_clientVar;',
+          );
+        },
+      );
+
+  Iterable<Method> _parseMethods(ClassElement element, String baseUrl) =>
+      element.methods
+          .where(
+            (MethodElement method) =>
+                _getMethodAnnotation(method) != null &&
+                method.isAbstract &&
+                method.returnType.isDartAsyncFuture,
+          )
+          .map((MethodElement m) => _generateMethod(m, baseUrl));
 
   Method _generateMethod(MethodElement m, String baseUrl) {
-    final method = _getMethodAnnotation(m);
-    final multipart = _hasAnnotation(m, chopper.Multipart);
-    final factoryConverter = _getFactoryConverterAnnotation(m);
-
-    final body = _getAnnotation(m, chopper.Body);
-    final paths = _getAnnotations(m, chopper.Path);
-    final queries = _getAnnotations(m, chopper.Query);
-    final queryMap = _getAnnotation(m, chopper.QueryMap);
-    final fields = _getAnnotations(m, chopper.Field);
-    final fieldMap = _getAnnotation(m, chopper.FieldMap);
-    final parts = _getAnnotations(m, chopper.Part);
-    final partMap = _getAnnotation(m, chopper.PartMap);
-    final fileFields = _getAnnotations(m, chopper.PartFile);
-    final fileFieldMap = _getAnnotation(m, chopper.PartFileMap);
-
-    final headers = _generateHeaders(m, method!);
-    final url = _generateUrl(method, paths, baseUrl);
-    final responseType = _getResponseType(m.returnType);
-    final responseInnerType =
+    final ConstantReader? method = _getMethodAnnotation(m);
+    final bool multipart = _hasAnnotation(m, chopper.Multipart);
+    final ConstantReader? factoryConverter = _getFactoryConverterAnnotation(m);
+
+    final Map<String, ConstantReader> body = _getAnnotation(m, chopper.Body);
+    final Map<ParameterElement, ConstantReader> paths =
+        _getAnnotations(m, chopper.Path);
+    final Map<ParameterElement, ConstantReader> queries =
+        _getAnnotations(m, chopper.Query);
+    final Map<String, ConstantReader> queryMap =
+        _getAnnotation(m, chopper.QueryMap);
+    final Map<ParameterElement, ConstantReader> fields =
+        _getAnnotations(m, chopper.Field);
+    final Map<String, ConstantReader> fieldMap =
+        _getAnnotation(m, chopper.FieldMap);
+    final Map<ParameterElement, ConstantReader> parts =
+        _getAnnotations(m, chopper.Part);
+    final Map<String, ConstantReader> partMap =
+        _getAnnotation(m, chopper.PartMap);
+    final Map<ParameterElement, ConstantReader> fileFields =
+        _getAnnotations(m, chopper.PartFile);
+    final Map<String, ConstantReader> fileFieldMap =
+        _getAnnotation(m, chopper.PartFileMap);
+
+    final Code? headers = _generateHeaders(m, method!);
+    final Expression url = _generateUrl(method, paths, baseUrl);
+    final DartType? responseType = _getResponseType(m.returnType);
+    final DartType? responseInnerType =
         _getResponseInnerType(m.returnType) ?? responseType;
 
-    return Method((b) {
+    return Method((MethodBuilder b) {
       b.annotations.add(refer('override'));
       b.name = m.displayName;
 
@@ -163,7 +173,7 @@ class ChopperGenerator extends GeneratorForAnnotation<chopper.ChopperApi> {
         m.parameters.where((p) => p.isNamed).map(buildNamedParam),
       );
 
-      final blocks = [
+      final List<Code> blocks = [
         url.assignFinal(_urlVar).statement,
       ];
 
@@ -171,29 +181,48 @@ class ChopperGenerator extends GeneratorForAnnotation<chopper.ChopperApi> {
         blocks.add(_generateMap(queries).assignFinal(_parametersVar).statement);
       }
 
-      final hasQueryMap = queryMap.isNotEmpty;
+      // Build an iterable of all the parameters that are nullable
+      final Iterable<String> optionalNullableParameters = [
+        ...m.parameters.where((p) => p.isOptionalPositional),
+        ...m.parameters.where((p) => p.isNamed),
+      ].where((el) => el.type.isNullable).map((el) => el.name);
+
+      final bool hasQueryMap = queryMap.isNotEmpty;
       if (hasQueryMap) {
         if (queries.isNotEmpty) {
           blocks.add(refer('$_parametersVar.addAll').call(
-            [refer(queryMap.keys.first)],
+            [
+              // Check if the parameter is nullable
+              optionalNullableParameters.contains(queryMap.keys.first)
+                  ? refer(queryMap.keys.first).ifNullThen(refer('{}'))
+                  : refer(queryMap.keys.first),
+            ],
           ).statement);
         } else {
           blocks.add(
-            refer(queryMap.keys.first).assignFinal(_parametersVar).statement,
+            // Check if the parameter is nullable
+            optionalNullableParameters.contains(queryMap.keys.first)
+                ? refer(queryMap.keys.first)
+                    .ifNullThen(refer('{}'))
+                    .assignFinal(_parametersVar)
+                    .statement
+                : refer(queryMap.keys.first)
+                    .assignFinal(_parametersVar)
+                    .statement,
           );
         }
       }
 
-      final hasQuery = hasQueryMap || queries.isNotEmpty;
+      final bool hasQuery = hasQueryMap || queries.isNotEmpty;
 
       if (headers != null) {
         blocks.add(headers);
       }
 
-      final methodOptionalBody = getMethodOptionalBody(method);
-      final methodName = getMethodName(method);
-      final methodUrl = getMethodPath(method);
-      var hasBody = body.isNotEmpty || fields.isNotEmpty;
+      final bool methodOptionalBody = getMethodOptionalBody(method);
+      final String methodName = getMethodName(method);
+      final String methodUrl = getMethodPath(method);
+      bool hasBody = body.isNotEmpty || fields.isNotEmpty;
       if (hasBody) {
         if (body.isNotEmpty) {
           blocks.add(
@@ -206,7 +235,7 @@ class ChopperGenerator extends GeneratorForAnnotation<chopper.ChopperApi> {
         }
       }
 
-      final hasFieldMap = fieldMap.isNotEmpty;
+      final bool hasFieldMap = fieldMap.isNotEmpty;
       if (hasFieldMap) {
         if (hasBody) {
           blocks.add(refer('$_bodyVar.addAll').call(
@@ -221,14 +250,14 @@ class ChopperGenerator extends GeneratorForAnnotation<chopper.ChopperApi> {
 
       hasBody = hasBody || hasFieldMap;
 
-      var hasParts =
-          multipart == true && (parts.isNotEmpty || fileFields.isNotEmpty);
+      bool hasParts = multipart && (parts.isNotEmpty || fileFields.isNotEmpty);
       if (hasParts) {
         blocks.add(
-            _generateList(parts, fileFields).assignFinal(_partsVar).statement);
+          _generateList(parts, fileFields).assignFinal(_partsVar).statement,
+        );
       }
 
-      final hasPartMap = multipart == true && partMap.isNotEmpty;
+      final bool hasPartMap = multipart && partMap.isNotEmpty;
       if (hasPartMap) {
         if (hasParts) {
           blocks.add(refer('$_partsVar.addAll').call(
@@ -241,7 +270,7 @@ class ChopperGenerator extends GeneratorForAnnotation<chopper.ChopperApi> {
         }
       }
 
-      final hasFileFilesMap = multipart == true && fileFieldMap.isNotEmpty;
+      final bool hasFileFilesMap = multipart && fileFieldMap.isNotEmpty;
       if (hasFileFilesMap) {
         if (hasParts || hasPartMap) {
           blocks.add(refer('$_partsVar.addAll').call(
@@ -275,26 +304,30 @@ class ChopperGenerator extends GeneratorForAnnotation<chopper.ChopperApi> {
         hasParts: hasParts,
       ).assignFinal(_requestVar).statement);
 
-      final namedArguments = <String, Expression>{};
+      final Map<String, Expression> namedArguments = {};
 
-      final requestFactory = factoryConverter?.peek('request');
+      final ConstantReader? requestFactory = factoryConverter?.peek('request');
       if (requestFactory != null) {
-        final func = requestFactory.objectValue.toFunctionValue();
+        final ExecutableElement? func =
+            requestFactory.objectValue.toFunctionValue();
         namedArguments['requestConverter'] = refer(_factoryForFunction(func!));
       }
 
-      final responseFactory = factoryConverter?.peek('response');
+      final ConstantReader? responseFactory =
+          factoryConverter?.peek('response');
       if (responseFactory != null) {
-        final func = responseFactory.objectValue.toFunctionValue();
+        final ExecutableElement? func =
+            responseFactory.objectValue.toFunctionValue();
         namedArguments['responseConverter'] = refer(_factoryForFunction(func!));
       }
 
-      final typeArguments = <Reference>[];
+      final List<Reference> typeArguments = [];
       if (responseType != null) {
         typeArguments
             .add(refer(responseType.getDisplayString(withNullability: false)));
         typeArguments.add(
-            refer(responseInnerType!.getDisplayString(withNullability: false)));
+          refer(responseInnerType!.getDisplayString(withNullability: false)),
+        );
       }
 
       blocks.add(refer('$_clientVar.send')
@@ -306,39 +339,42 @@ class ChopperGenerator extends GeneratorForAnnotation<chopper.ChopperApi> {
     });
   }
 
-  String _factoryForFunction(FunctionTypedElement function) {
-    if (function.enclosingElement is ClassElement) {
-      return '${function.enclosingElement!.name}.${function.name}';
-    }
-    return function.name!;
-  }
+  String _factoryForFunction(FunctionTypedElement function) =>
+      function.enclosingElement is ClassElement
+          ? '${function.enclosingElement!.name}.${function.name}'
+          : function.name!;
 
   Map<String, ConstantReader> _getAnnotation(MethodElement method, Type type) {
-    var annotation;
-    var name = '';
-    for (final p in method.parameters) {
-      dynamic a = _typeChecker(type).firstAnnotationOf(p);
+    DartObject? annotation;
+    String name = '';
+
+    for (final ParameterElement p in method.parameters) {
+      DartObject? a = _typeChecker(type).firstAnnotationOf(p);
       if (annotation != null && a != null) {
         throw Exception(
-            'Too many $type annotation for \'${method.displayName}\'');
+          'Too many $type annotation for \'${method.displayName}\'',
+        );
       } else if (annotation == null && a != null) {
         annotation = a;
         name = p.displayName;
       }
     }
-    if (annotation == null) return {};
-    return {name: ConstantReader(annotation)};
+
+    return annotation == null ? {} : {name: ConstantReader(annotation)};
   }
 
   Map<ParameterElement, ConstantReader> _getAnnotations(
-      MethodElement m, Type type) {
-    var annotation = <ParameterElement, ConstantReader>{};
-    for (final p in m.parameters) {
-      final a = _typeChecker(type).firstAnnotationOf(p);
+    MethodElement m,
+    Type type,
+  ) {
+    Map<ParameterElement, ConstantReader> annotation = {};
+    for (final ParameterElement p in m.parameters) {
+      final DartObject? a = _typeChecker(type).firstAnnotationOf(p);
       if (a != null) {
         annotation[p] = ConstantReader(a);
       }
     }
+
     return annotation;
   }
 
@@ -346,28 +382,28 @@ class ChopperGenerator extends GeneratorForAnnotation<chopper.ChopperApi> {
 
   ConstantReader? _getMethodAnnotation(MethodElement method) {
     for (final type in _methodsAnnotations) {
-      final annotation = _typeChecker(type)
+      final DartObject? annotation = _typeChecker(type)
           .firstAnnotationOf(method, throwOnUnresolved: false);
-      if (annotation != null) return ConstantReader(annotation);
+      if (annotation != null) {
+        return ConstantReader(annotation);
+      }
     }
+
     return null;
   }
 
   ConstantReader? _getFactoryConverterAnnotation(MethodElement method) {
-    final annotation = _typeChecker(chopper.FactoryConverter)
+    final DartObject? annotation = _typeChecker(chopper.FactoryConverter)
         .firstAnnotationOf(method, throwOnUnresolved: false);
-    if (annotation != null) return ConstantReader(annotation);
-    return null;
-  }
 
-  bool _hasAnnotation(MethodElement method, Type type) {
-    final annotation =
-        _typeChecker(type).firstAnnotationOf(method, throwOnUnresolved: false);
-
-    return annotation != null;
+    return annotation != null ? ConstantReader(annotation) : null;
   }
 
-  final _methodsAnnotations = const [
+  bool _hasAnnotation(MethodElement method, Type type) =>
+      _typeChecker(type).firstAnnotationOf(method, throwOnUnresolved: false) !=
+      null;
+
+  final List<Type> _methodsAnnotations = const [
     chopper.Get,
     chopper.Post,
     chopper.Delete,
@@ -378,18 +414,15 @@ class ChopperGenerator extends GeneratorForAnnotation<chopper.ChopperApi> {
     chopper.Options,
   ];
 
-  DartType? _genericOf(DartType? type) {
-    return type is InterfaceType && type.typeArguments.isNotEmpty
-        ? type.typeArguments.first
-        : null;
-  }
+  DartType? _genericOf(DartType? type) =>
+      type is InterfaceType && type.typeArguments.isNotEmpty
+          ? type.typeArguments.first
+          : null;
 
-  DartType? _getResponseType(DartType type) {
-    return _genericOf(_genericOf(type));
-  }
+  DartType? _getResponseType(DartType type) => _genericOf(_genericOf(type));
 
   DartType? _getResponseInnerType(DartType type) {
-    final generic = _genericOf(type);
+    final DartType? generic = _genericOf(type);
 
     if (generic == null ||
         _typeChecker(Map).isExactlyType(type) ||
@@ -408,9 +441,9 @@ class ChopperGenerator extends GeneratorForAnnotation<chopper.ChopperApi> {
     Map<ParameterElement, ConstantReader> paths,
     String baseUrl,
   ) {
-    var path = getMethodPath(method);
+    String path = getMethodPath(method);
     paths.forEach((p, ConstantReader r) {
-      final name = r.peek('name')?.stringValue ?? p.displayName;
+      final String name = r.peek('name')?.stringValue ?? p.displayName;
       path = path.replaceFirst('{$name}', '\${${p.displayName}}');
     });
 
@@ -439,13 +472,13 @@ class ChopperGenerator extends GeneratorForAnnotation<chopper.ChopperApi> {
     bool useQueries = false,
     bool useHeaders = false,
   }) {
-    final params = <Expression>[
+    final List<Expression> params = [
       literal(getMethodName(method)),
       refer(_urlVar),
       refer('$_clientVar.$_baseUrlVar'),
     ];
 
-    final namedParams = <String, Expression>{};
+    final Map<String, Expression> namedParams = {};
 
     if (hasBody) {
       namedParams['body'] = refer(_bodyVar);
@@ -468,9 +501,9 @@ class ChopperGenerator extends GeneratorForAnnotation<chopper.ChopperApi> {
   }
 
   Expression _generateMap(Map<ParameterElement, ConstantReader> queries) {
-    final map = {};
-    queries.forEach((p, ConstantReader r) {
-      final name = r.peek('name')?.stringValue ?? p.displayName;
+    final Map map = {};
+    queries.forEach((ParameterElement p, ConstantReader r) {
+      final String name = r.peek('name')?.stringValue ?? p.displayName;
       map[literal(name)] = refer(p.displayName);
     });
 
@@ -481,21 +514,21 @@ class ChopperGenerator extends GeneratorForAnnotation<chopper.ChopperApi> {
     Map<ParameterElement, ConstantReader> parts,
     Map<ParameterElement, ConstantReader> fileFields,
   ) {
-    final list = [];
+    final List list = [];
     parts.forEach((p, ConstantReader r) {
-      final name = r.peek('name')?.stringValue ?? p.displayName;
-      final params = <Expression>[
+      final String name = r.peek('name')?.stringValue ?? p.displayName;
+      final List<Expression> params = [
         literal(name),
         refer(p.displayName),
       ];
 
       list.add(refer(
-              'PartValue<${p.type.getDisplayString(withNullability: p.type.isNullable)}>')
-          .newInstance(params));
+        'PartValue<${p.type.getDisplayString(withNullability: p.type.isNullable)}>',
+      ).newInstance(params));
     });
     fileFields.forEach((p, ConstantReader r) {
-      final name = r.peek('name')?.stringValue ?? p.displayName;
-      final params = <Expression>[
+      final String name = r.peek('name')?.stringValue ?? p.displayName;
+      final List<Expression> params = [
         literal(name),
         refer(p.displayName),
       ];
@@ -505,18 +538,20 @@ class ChopperGenerator extends GeneratorForAnnotation<chopper.ChopperApi> {
             .newInstance(params),
       );
     });
+
     return literalList(list, refer('PartValue'));
   }
 
   Code? _generateHeaders(MethodElement methodElement, ConstantReader method) {
-    final codeBuffer = StringBuffer('')..writeln('{');
+    final StringBuffer codeBuffer = StringBuffer('')..writeln('{');
 
     // Search for @Header anotation in method parameters
-    final annotations = _getAnnotations(methodElement, chopper.Header);
+    final Map<ParameterElement, ConstantReader> annotations =
+        _getAnnotations(methodElement, chopper.Header);
 
     annotations.forEach((parameter, ConstantReader annotation) {
-      final paramName = parameter.displayName;
-      final name = annotation.peek('name')?.stringValue ?? paramName;
+      final String paramName = parameter.displayName;
+      final String name = annotation.peek('name')?.stringValue ?? paramName;
 
       if (parameter.type.isNullable) {
         codeBuffer.writeln('if ($paramName != null) \'$name\': $paramName,');
@@ -525,10 +560,11 @@ class ChopperGenerator extends GeneratorForAnnotation<chopper.ChopperApi> {
       }
     });
 
-    final headersReader = method.peek('headers');
+    final ConstantReader? headersReader = method.peek('headers');
     if (headersReader == null) return null;
 
-    final methodAnnotations = headersReader.mapValue;
+    final Map<DartObject?, DartObject?> methodAnnotations =
+        headersReader.mapValue;
 
     methodAnnotations.forEach((headerName, headerValue) {
       if (headerName != null && headerValue != null) {
@@ -539,12 +575,9 @@ class ChopperGenerator extends GeneratorForAnnotation<chopper.ChopperApi> {
     });
 
     codeBuffer.writeln('};');
-    final code = codeBuffer.toString();
-    if (code == '{\n};\n') {
-      return null;
-    }
+    final String code = codeBuffer.toString();
 
-    return Code('final $_headersVar = $code');
+    return code == '{\n};\n' ? null : Code('final $_headersVar = $code');
   }
 }
 
@@ -567,45 +600,41 @@ extension DartTypeExtension on DartType {
 }
 
 // All positional required params must support nullability
-Parameter buildRequiredPositionalParam(ParameterElement p) {
-  return Parameter(
-    (pb) => pb
-      ..name = p.name
-      ..type = Reference(
-        p.type.getDisplayString(withNullability: p.type.isNullable),
-      ),
-  );
-}
+Parameter buildRequiredPositionalParam(ParameterElement p) => Parameter(
+      (ParameterBuilder pb) => pb
+        ..name = p.name
+        ..type = Reference(
+          p.type.getDisplayString(withNullability: p.type.isNullable),
+        ),
+    );
 
 // All optional positional params must support nullability
-Parameter buildOptionalPositionalParam(ParameterElement p) {
-  return Parameter((pb) {
-    pb
-      ..name = p.name
-      ..type = Reference(
-        p.type.getDisplayString(withNullability: p.type.isNullable),
-      );
+Parameter buildOptionalPositionalParam(ParameterElement p) =>
+    Parameter((ParameterBuilder pb) {
+      pb
+        ..name = p.name
+        ..type = Reference(
+          p.type.getDisplayString(withNullability: p.type.isNullable),
+        );
 
-    if (p.defaultValueCode != null) {
-      pb.defaultTo = Code(p.defaultValueCode!);
-    }
-  });
-}
+      if (p.defaultValueCode != null) {
+        pb.defaultTo = Code(p.defaultValueCode!);
+      }
+    });
 
 // Named params can be optional or required, they also need to support
 // nullability
-Parameter buildNamedParam(ParameterElement p) {
-  return Parameter((pb) {
-    pb
-      ..named = true
-      ..name = p.name
-      ..required = p.isRequiredNamed
-      ..type = Reference(
-        p.type.getDisplayString(withNullability: p.type.isNullable),
-      );
+Parameter buildNamedParam(ParameterElement p) =>
+    Parameter((ParameterBuilder pb) {
+      pb
+        ..named = true
+        ..name = p.name
+        ..required = p.isRequiredNamed
+        ..type = Reference(
+          p.type.getDisplayString(withNullability: p.type.isNullable),
+        );
 
-    if (p.defaultValueCode != null) {
-      pb.defaultTo = Code(p.defaultValueCode!);
-    }
-  });
-}
+      if (p.defaultValueCode != null) {
+        pb.defaultTo = Code(p.defaultValueCode!);
+      }
+    });
diff --git a/chopper_generator/pubspec.yaml b/chopper_generator/pubspec.yaml
index 8c98c3b8..a5804be1 100644
--- a/chopper_generator/pubspec.yaml
+++ b/chopper_generator/pubspec.yaml
@@ -1,26 +1,27 @@
 name: chopper_generator
 description: Chopper is an http client generator using source_gen, inspired by Retrofit
-version: 4.0.6
+version: 5.0.0
 documentation: https://hadrien-lejard.gitbook.io/chopper
 repository: https://github.com/lejard-h/chopper
 
 environment:
-  sdk: ">=2.12.0 <3.0.0"
+  sdk: ">=2.17.0 <3.0.0"
 
 dependencies:
-  analyzer: ^4.1.0
+  analyzer: ">=4.1.0 <4.3.0"
   build: ^2.0.0
   built_collection: ^5.0.0
-  chopper: ^4.0.0
-  code_builder: ^4.0.0
+  chopper: ^5.0.0
+  code_builder: ^4.1.0
   dart_style: ^2.0.0
   logging: ^1.0.0
   meta: ^1.3.0
   source_gen: ^1.0.0
 
 dev_dependencies:
-  pedantic: ^1.11.0
-  test: ^1.15.4
+  test: ^1.16.4
+  dart_code_metrics: ^4.8.1
+  lints: ^2.0.0
 
 dependency_overrides:
   # Comment before publish
diff --git a/example/analysis_options.yaml b/example/analysis_options.yaml
new file mode 100644
index 00000000..7061686f
--- /dev/null
+++ b/example/analysis_options.yaml
@@ -0,0 +1,32 @@
+include: package:lints/recommended.yaml
+
+analyzer:
+  exclude:
+    - "**.g.dart"
+    - "**.chopper.dart"
+    - "**.mocks.dart"
+  plugins:
+    - dart_code_metrics
+
+dart_code_metrics:
+  metrics:
+    cyclomatic-complexity: 20
+    number-of-arguments: 4
+    maximum-nesting-level: 5
+  metrics-exclude:
+    - test/**
+  rules:
+    - newline-before-return
+    - no-boolean-literal-compare
+    - no-empty-block
+    - prefer-trailing-comma
+    - prefer-conditional-expressions
+    - no-equal-then-else
+  anti-patterns:
+    - long-method
+    - long-parameter-list
+
+linter:
+  rules:
+    avoid_print: false
+    prefer_single_quotes: true
diff --git a/example/bin/main_built_value.dart b/example/bin/main_built_value.dart
index 8ebaff5b..9f87becc 100644
--- a/example/bin/main_built_value.dart
+++ b/example/bin/main_built_value.dart
@@ -1,28 +1,33 @@
+import 'dart:async';
+
 import 'package:built_collection/built_collection.dart';
 import 'package:built_value/serializer.dart';
+import 'package:built_value/standard_json_plugin.dart';
 import 'package:chopper/chopper.dart';
 import 'package:chopper_example/built_value_resource.dart';
 import 'package:chopper_example/built_value_serializers.dart';
-import 'package:built_value/standard_json_plugin.dart';
 import 'package:http/http.dart' as http;
 import 'package:http/testing.dart';
 
 final jsonSerializers =
-    (serializers.toBuilder()..addPlugin(new StandardJsonPlugin())).build();
+    (serializers.toBuilder()..addPlugin(StandardJsonPlugin())).build();
 
 /// Simple client to have working example without remote server
 final client = MockClient((req) async {
-  if (req.method == 'POST')
+  if (req.method == 'POST') {
     return http.Response('{"type":"Fatal","message":"fatal erorr"}', 500);
-  if (req.url.path == '/resources/list')
+  }
+  if (req.url.path == '/resources/list') {
     return http.Response('[{"id":"1","name":"Foo"}]', 200);
+  }
+
   return http.Response('{"id":"1","name":"Foo"}', 200);
 });
 
 main() async {
-  final chopper = new ChopperClient(
+  final chopper = ChopperClient(
     client: client,
-    baseUrl: "http://localhost:8000",
+    baseUrl: 'http://localhost:8000',
     converter: BuiltValueConverter(),
     errorConverter: BuiltValueConverter(),
     services: [
@@ -33,7 +38,7 @@ main() async {
 
   final myService = chopper.getService<MyService>();
 
-  final response1 = await myService.getResource("1");
+  final response1 = await myService.getResource('1');
   print('response 1: ${response1.body}'); // undecoded String
 
   final response2 = await myService.getTypedResource();
@@ -44,8 +49,8 @@ main() async {
 
   try {
     final builder = ResourceBuilder()
-      ..id = "3"
-      ..name = "Super Name";
+      ..id = '3'
+      ..name = 'Super Name';
     await myService.newResource(builder.build());
   } on Response catch (error) {
     print(error.body);
@@ -56,12 +61,10 @@ class BuiltValueConverter extends JsonConverter {
   T? _deserialize<T>(dynamic value) {
     final serializer = jsonSerializers.serializerForType(T) as Serializer<T>?;
     if (serializer == null) {
-      throw Exception('No serializer for type ${T}');
+      throw Exception('No serializer for type $T');
     }
-    return jsonSerializers.deserializeWith<T>(
-      serializer,
-      value,
-    );
+
+    return jsonSerializers.deserializeWith<T>(serializer, value);
   }
 
   BuiltList<T> _deserializeListOf<T>(Iterable value) => BuiltList(
@@ -75,19 +78,24 @@ class BuiltValueConverter extends JsonConverter {
     if (entity is T) return entity;
 
     try {
-      if (entity is List) return _deserializeListOf<T>(entity);
-      return _deserialize<T>(entity);
+      return entity is List
+          ? _deserializeListOf<T>(entity)
+          : _deserialize<T>(entity);
     } catch (e) {
       print(e);
+
       return null;
     }
   }
 
   @override
-  Response<ResultType> convertResponse<ResultType, Item>(Response response) {
+  FutureOr<Response<ResultType>> convertResponse<ResultType, Item>(
+    Response response,
+  ) async {
     // use [JsonConverter] to decode json
-    final jsonRes = super.convertResponse(response);
+    final Response jsonRes = await super.convertResponse(response);
     final body = _decode<Item>(jsonRes.body);
+
     return jsonRes.copyWith<ResultType>(body: body);
   }
 
diff --git a/example/bin/main_json_serializable.dart b/example/bin/main_json_serializable.dart
index 0d09e8f8..956014f5 100644
--- a/example/bin/main_json_serializable.dart
+++ b/example/bin/main_json_serializable.dart
@@ -1,16 +1,19 @@
-import "dart:async";
+import 'dart:async';
+
 import 'package:chopper/chopper.dart';
 import 'package:chopper_example/json_serializable.dart';
-
 import 'package:http/http.dart' as http;
 import 'package:http/testing.dart';
 
 /// Simple client to have working example without remote server
 final client = MockClient((req) async {
-  if (req.method == 'POST')
+  if (req.method == 'POST') {
     return http.Response('{"type":"Fatal","message":"fatal erorr"}', 500);
-  if (req.method == 'GET' && req.headers['test'] == 'list')
+  }
+  if (req.method == 'GET' && req.headers['test'] == 'list') {
     return http.Response('[{"id":"1","name":"Foo"}]', 200);
+  }
+
   return http.Response('{"id":"1","name":"Foo"}', 200);
 });
 
@@ -21,7 +24,7 @@ main() async {
 
   final chopper = ChopperClient(
     client: client,
-    baseUrl: "http://localhost:8000",
+    baseUrl: 'http://localhost:8000',
     // bind your object factories here
     converter: converter,
     errorConverter: converter,
@@ -35,7 +38,7 @@ main() async {
 
   final myService = chopper.getService<MyService>();
 
-  final response1 = await myService.getResource("1");
+  final response1 = await myService.getResource('1');
   print('response 1: ${response1.body}'); // undecoded String
 
   final response2 = await myService.getResources();
@@ -44,11 +47,11 @@ main() async {
   final response3 = await myService.getTypedResource();
   print('response 3: ${response3.body}'); // decoded Resource
 
-  final response4 = await myService.getMapResource("1");
+  final response4 = await myService.getMapResource('1');
   print('response 4: ${response4.body}'); // undecoded Resource
 
   try {
-    await myService.newResource(Resource("3", "Super Name"));
+    await myService.newResource(Resource('3', 'Super Name'));
   } on Response catch (error) {
     print(error.body);
   }
@@ -56,8 +59,8 @@ main() async {
 
 Future<Request> authHeader(Request request) async => applyHeader(
       request,
-      "Authorization",
-      "42",
+      'Authorization',
+      '42',
     );
 
 typedef JsonFactory<T> = T Function(Map<String, dynamic> json);
@@ -91,20 +94,24 @@ class JsonSerializableConverter extends JsonConverter {
   }
 
   @override
-  Response<ResultType> convertResponse<ResultType, Item>(Response response) {
+  FutureOr<Response<ResultType>> convertResponse<ResultType, Item>(
+    Response response,
+  ) async {
     // use [JsonConverter] to decode json
-    final jsonRes = super.convertResponse(response);
+    final jsonRes = await super.convertResponse(response);
 
     return jsonRes.copyWith<ResultType>(body: _decode<Item>(jsonRes.body));
   }
 
   @override
   // all objects should implements toJson method
+  // ignore: unnecessary_overrides
   Request convertRequest(Request request) => super.convertRequest(request);
 
-  Response convertError<ResultType, Item>(Response response) {
+  @override
+  FutureOr<Response> convertError<ResultType, Item>(Response response) async {
     // use [JsonConverter] to decode json
-    final jsonRes = super.convertError(response);
+    final jsonRes = await super.convertError(response);
 
     return jsonRes.copyWith<ResourceError>(
       body: ResourceError.fromJsonFactory(jsonRes.body),
diff --git a/example/lib/built_value_resource.dart b/example/lib/built_value_resource.dart
index 6ea4e35b..9e30c3ed 100644
--- a/example/lib/built_value_resource.dart
+++ b/example/lib/built_value_resource.dart
@@ -7,44 +7,51 @@ import 'package:built_value/built_value.dart';
 import 'package:built_value/serializer.dart';
 import 'package:chopper/chopper.dart';
 
-part 'built_value_resource.g.dart';
 part 'built_value_resource.chopper.dart';
+part 'built_value_resource.g.dart';
 
 abstract class Resource implements Built<Resource, ResourceBuilder> {
   String get id;
+
   String get name;
 
   static Serializer<Resource> get serializer => _$resourceSerializer;
 
-  factory Resource([updates(ResourceBuilder b)]) = _$Resource;
+  factory Resource([Function(ResourceBuilder b) updates]) = _$Resource;
+
   Resource._();
 }
 
 abstract class ResourceError
     implements Built<ResourceError, ResourceErrorBuilder> {
   String get type;
+
   String get message;
 
   static Serializer<ResourceError> get serializer => _$resourceErrorSerializer;
 
-  factory ResourceError([updates(ResourceErrorBuilder b)]) = _$ResourceError;
+  factory ResourceError([Function(ResourceErrorBuilder b) updates]) =
+      _$ResourceError;
+
   ResourceError._();
 }
 
-@ChopperApi(baseUrl: "/resources")
+@ChopperApi(baseUrl: '/resources')
 abstract class MyService extends ChopperService {
   static MyService create([ChopperClient? client]) => _$MyService(client);
 
-  @Get(path: "/{id}/")
+  @Get(path: '/{id}/')
   Future<Response> getResource(@Path() String id);
 
-  @Get(path: "/list")
+  @Get(path: '/list')
   Future<Response<BuiltList<Resource>>> getBuiltListResources();
 
-  @Get(path: "/", headers: const {"foo": "bar"})
+  @Get(path: '/', headers: {'foo': 'bar'})
   Future<Response<Resource>> getTypedResource();
 
   @Post()
-  Future<Response<Resource>> newResource(@Body() Resource resource,
-      {@Header() String? name});
+  Future<Response<Resource>> newResource(
+    @Body() Resource resource, {
+    @Header() String? name,
+  });
 }
diff --git a/example/lib/built_value_resource.g.dart b/example/lib/built_value_resource.g.dart
index 8030092d..bc969e05 100644
--- a/example/lib/built_value_resource.g.dart
+++ b/example/lib/built_value_resource.g.dart
@@ -36,17 +36,17 @@ class _$ResourceSerializer implements StructuredSerializer<Resource> {
 
     final iterator = serialized.iterator;
     while (iterator.moveNext()) {
-      final key = iterator.current as String;
+      final key = iterator.current! as String;
       iterator.moveNext();
       final Object? value = iterator.current;
       switch (key) {
         case 'id':
           result.id = serializers.deserialize(value,
-              specifiedType: const FullType(String)) as String;
+              specifiedType: const FullType(String))! as String;
           break;
         case 'name':
           result.name = serializers.deserialize(value,
-              specifiedType: const FullType(String)) as String;
+              specifiedType: const FullType(String))! as String;
           break;
       }
     }
@@ -83,17 +83,17 @@ class _$ResourceErrorSerializer implements StructuredSerializer<ResourceError> {
 
     final iterator = serialized.iterator;
     while (iterator.moveNext()) {
-      final key = iterator.current as String;
+      final key = iterator.current! as String;
       iterator.moveNext();
       final Object? value = iterator.current;
       switch (key) {
         case 'type':
           result.type = serializers.deserialize(value,
-              specifiedType: const FullType(String)) as String;
+              specifiedType: const FullType(String))! as String;
           break;
         case 'message':
           result.message = serializers.deserialize(value,
-              specifiedType: const FullType(String)) as String;
+              specifiedType: const FullType(String))! as String;
           break;
       }
     }
@@ -109,11 +109,11 @@ class _$Resource extends Resource {
   final String name;
 
   factory _$Resource([void Function(ResourceBuilder)? updates]) =>
-      (new ResourceBuilder()..update(updates)).build();
+      (new ResourceBuilder()..update(updates))._build();
 
   _$Resource._({required this.id, required this.name}) : super._() {
-    BuiltValueNullFieldError.checkNotNull(id, 'Resource', 'id');
-    BuiltValueNullFieldError.checkNotNull(name, 'Resource', 'name');
+    BuiltValueNullFieldError.checkNotNull(id, r'Resource', 'id');
+    BuiltValueNullFieldError.checkNotNull(name, r'Resource', 'name');
   }
 
   @override
@@ -136,7 +136,7 @@ class _$Resource extends Resource {
 
   @override
   String toString() {
-    return (newBuiltValueToStringHelper('Resource')
+    return (newBuiltValueToStringHelper(r'Resource')
           ..add('id', id)
           ..add('name', name))
         .toString();
@@ -178,12 +178,14 @@ class ResourceBuilder implements Builder<Resource, ResourceBuilder> {
   }
 
   @override
-  _$Resource build() {
+  Resource build() => _build();
+
+  _$Resource _build() {
     final _$result = _$v ??
         new _$Resource._(
-            id: BuiltValueNullFieldError.checkNotNull(id, 'Resource', 'id'),
+            id: BuiltValueNullFieldError.checkNotNull(id, r'Resource', 'id'),
             name: BuiltValueNullFieldError.checkNotNull(
-                name, 'Resource', 'name'));
+                name, r'Resource', 'name'));
     replace(_$result);
     return _$result;
   }
@@ -196,11 +198,11 @@ class _$ResourceError extends ResourceError {
   final String message;
 
   factory _$ResourceError([void Function(ResourceErrorBuilder)? updates]) =>
-      (new ResourceErrorBuilder()..update(updates)).build();
+      (new ResourceErrorBuilder()..update(updates))._build();
 
   _$ResourceError._({required this.type, required this.message}) : super._() {
-    BuiltValueNullFieldError.checkNotNull(type, 'ResourceError', 'type');
-    BuiltValueNullFieldError.checkNotNull(message, 'ResourceError', 'message');
+    BuiltValueNullFieldError.checkNotNull(type, r'ResourceError', 'type');
+    BuiltValueNullFieldError.checkNotNull(message, r'ResourceError', 'message');
   }
 
   @override
@@ -225,7 +227,7 @@ class _$ResourceError extends ResourceError {
 
   @override
   String toString() {
-    return (newBuiltValueToStringHelper('ResourceError')
+    return (newBuiltValueToStringHelper(r'ResourceError')
           ..add('type', type)
           ..add('message', message))
         .toString();
@@ -268,16 +270,18 @@ class ResourceErrorBuilder
   }
 
   @override
-  _$ResourceError build() {
+  ResourceError build() => _build();
+
+  _$ResourceError _build() {
     final _$result = _$v ??
         new _$ResourceError._(
             type: BuiltValueNullFieldError.checkNotNull(
-                type, 'ResourceError', 'type'),
+                type, r'ResourceError', 'type'),
             message: BuiltValueNullFieldError.checkNotNull(
-                message, 'ResourceError', 'message'));
+                message, r'ResourceError', 'message'));
     replace(_$result);
     return _$result;
   }
 }
 
-// ignore_for_file: always_put_control_body_on_new_line,always_specify_types,annotate_overrides,avoid_annotating_with_dynamic,avoid_as,avoid_catches_without_on_clauses,avoid_returning_this,deprecated_member_use_from_same_package,lines_longer_than_80_chars,omit_local_variable_types,prefer_expression_function_bodies,sort_constructors_first,test_types_in_equals,unnecessary_const,unnecessary_new
+// ignore_for_file: always_put_control_body_on_new_line,always_specify_types,annotate_overrides,avoid_annotating_with_dynamic,avoid_as,avoid_catches_without_on_clauses,avoid_returning_this,deprecated_member_use_from_same_package,lines_longer_than_80_chars,no_leading_underscores_for_local_identifiers,omit_local_variable_types,prefer_expression_function_bodies,sort_constructors_first,test_types_in_equals,unnecessary_const,unnecessary_new,unnecessary_lambdas
diff --git a/example/lib/built_value_serializers.dart b/example/lib/built_value_serializers.dart
index cc8ef450..256983bf 100644
--- a/example/lib/built_value_serializers.dart
+++ b/example/lib/built_value_serializers.dart
@@ -1,12 +1,13 @@
 library serializers;
 
 import 'package:built_value/serializer.dart';
+
 import 'built_value_resource.dart';
 
 part 'built_value_serializers.g.dart';
 
 /// Collection of generated serializers for the built_value chat example.
-@SerializersFor(const [
+@SerializersFor([
   Resource,
   ResourceError,
 ])
diff --git a/example/lib/built_value_serializers.g.dart b/example/lib/built_value_serializers.g.dart
index dbad2232..699b3f08 100644
--- a/example/lib/built_value_serializers.g.dart
+++ b/example/lib/built_value_serializers.g.dart
@@ -11,4 +11,4 @@ Serializers _$serializers = (new Serializers().toBuilder()
       ..add(ResourceError.serializer))
     .build();
 
-// ignore_for_file: always_put_control_body_on_new_line,always_specify_types,annotate_overrides,avoid_annotating_with_dynamic,avoid_as,avoid_catches_without_on_clauses,avoid_returning_this,deprecated_member_use_from_same_package,lines_longer_than_80_chars,omit_local_variable_types,prefer_expression_function_bodies,sort_constructors_first,test_types_in_equals,unnecessary_const,unnecessary_new
+// ignore_for_file: always_put_control_body_on_new_line,always_specify_types,annotate_overrides,avoid_annotating_with_dynamic,avoid_as,avoid_catches_without_on_clauses,avoid_returning_this,deprecated_member_use_from_same_package,lines_longer_than_80_chars,no_leading_underscores_for_local_identifiers,omit_local_variable_types,prefer_expression_function_bodies,sort_constructors_first,test_types_in_equals,unnecessary_const,unnecessary_new,unnecessary_lambdas
diff --git a/example/lib/json_serializable.dart b/example/lib/json_serializable.dart
index 361f166a..4676bcab 100644
--- a/example/lib/json_serializable.dart
+++ b/example/lib/json_serializable.dart
@@ -3,8 +3,8 @@ import 'dart:async';
 import 'package:chopper/chopper.dart';
 import 'package:json_annotation/json_annotation.dart';
 
-part 'json_serializable.g.dart';
 part 'json_serializable.chopper.dart';
+part 'json_serializable.g.dart';
 
 @JsonSerializable()
 class Resource {
@@ -33,23 +33,25 @@ class ResourceError {
   Map<String, dynamic> toJson() => _$ResourceErrorToJson(this);
 }
 
-@ChopperApi(baseUrl: "/resources")
+@ChopperApi(baseUrl: '/resources')
 abstract class MyService extends ChopperService {
   static MyService create([ChopperClient? client]) => _$MyService(client);
 
-  @Get(path: "/{id}/")
+  @Get(path: '/{id}/')
   Future<Response> getResource(@Path() String id);
 
-  @Get(path: "/all", headers: const {"test": "list"})
+  @Get(path: '/all', headers: {'test': 'list'})
   Future<Response<List<Resource>>> getResources();
 
-  @Get(path: "/")
+  @Get(path: '/')
   Future<Response<Map>> getMapResource(@Query() String id);
 
-  @Get(path: "/", headers: const {"foo": "bar"})
+  @Get(path: '/', headers: {'foo': 'bar'})
   Future<Response<Resource>> getTypedResource();
 
   @Post()
-  Future<Response<Resource>> newResource(@Body() Resource resource,
-      {@Header() String? name});
+  Future<Response<Resource>> newResource(
+    @Body() Resource resource, {
+    @Header() String? name,
+  });
 }
diff --git a/example/pubspec.lock b/example/pubspec.lock
index fff2f649..f9411798 100644
--- a/example/pubspec.lock
+++ b/example/pubspec.lock
@@ -7,14 +7,28 @@ packages:
       name: _fe_analyzer_shared
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "34.0.0"
+    version: "40.0.0"
   analyzer:
     dependency: "direct main"
     description:
       name: analyzer
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "3.2.0"
+    version: "4.1.0"
+  analyzer_plugin:
+    dependency: transitive
+    description:
+      name: analyzer_plugin
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "0.10.0"
+  ansicolor:
+    dependency: transitive
+    description:
+      name: ansicolor
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "2.0.1"
   args:
     dependency: transitive
     description:
@@ -35,7 +49,7 @@ packages:
       name: build
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "2.2.1"
+    version: "2.3.0"
   build_config:
     dependency: transitive
     description:
@@ -49,21 +63,21 @@ packages:
       name: build_daemon
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "3.0.1"
+    version: "3.1.0"
   build_resolvers:
     dependency: transitive
     description:
       name: build_resolvers
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "2.0.6"
+    version: "2.0.9"
   build_runner:
     dependency: "direct dev"
     description:
       name: build_runner
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "2.1.7"
+    version: "2.1.11"
   build_runner_core:
     dependency: transitive
     description:
@@ -72,7 +86,7 @@ packages:
     source: hosted
     version: "7.2.3"
   built_collection:
-    dependency: transitive
+    dependency: "direct main"
     description:
       name: built_collection
       url: "https://pub.dartlang.org"
@@ -91,7 +105,7 @@ packages:
       name: built_value_generator
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "8.1.4"
+    version: "8.4.0"
   charcode:
     dependency: transitive
     description:
@@ -112,21 +126,14 @@ packages:
       path: "../chopper"
       relative: true
     source: path
-    version: "4.0.1"
+    version: "4.1.0"
   chopper_generator:
     dependency: "direct dev"
     description:
       path: "../chopper_generator"
       relative: true
     source: path
-    version: "4.0.2"
-  cli_util:
-    dependency: transitive
-    description:
-      name: cli_util
-      url: "https://pub.dartlang.org"
-    source: hosted
-    version: "0.3.5"
+    version: "4.0.3"
   code_builder:
     dependency: transitive
     description:
@@ -155,13 +162,27 @@ packages:
       url: "https://pub.dartlang.org"
     source: hosted
     version: "3.0.1"
+  csslib:
+    dependency: transitive
+    description:
+      name: csslib
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "0.17.2"
+  dart_code_metrics:
+    dependency: "direct dev"
+    description:
+      name: dart_code_metrics
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "4.16.0"
   dart_style:
     dependency: transitive
     description:
       name: dart_style
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "2.2.1"
+    version: "2.2.3"
   file:
     dependency: transitive
     description:
@@ -197,8 +218,15 @@ packages:
       url: "https://pub.dartlang.org"
     source: hosted
     version: "2.1.0"
-  http:
+  html:
     dependency: transitive
+    description:
+      name: html
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "0.15.0"
+  http:
+    dependency: "direct main"
     description:
       name: http
       url: "https://pub.dartlang.org"
@@ -245,7 +273,14 @@ packages:
       name: json_serializable
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "6.1.4"
+    version: "6.1.6"
+  lints:
+    dependency: "direct dev"
+    description:
+      name: lints
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "2.0.0"
   logging:
     dependency: transitive
     description:
@@ -288,6 +323,13 @@ packages:
       url: "https://pub.dartlang.org"
     source: hosted
     version: "1.8.1"
+  petitparser:
+    dependency: transitive
+    description:
+      name: petitparser
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "4.4.0"
   pool:
     dependency: transitive
     description:
@@ -336,14 +378,14 @@ packages:
       name: source_gen
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.2.1"
+    version: "1.2.2"
   source_helper:
     dependency: transitive
     description:
       name: source_helper
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.3.1"
+    version: "1.3.2"
   source_span:
     dependency: transitive
     description:
@@ -414,6 +456,13 @@ packages:
       url: "https://pub.dartlang.org"
     source: hosted
     version: "2.1.0"
+  xml:
+    dependency: transitive
+    description:
+      name: xml
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "5.3.1"
   yaml:
     dependency: transitive
     description:
@@ -422,4 +471,4 @@ packages:
     source: hosted
     version: "3.1.0"
 sdks:
-  dart: ">=2.16.0-100.0.dev <3.0.0"
+  dart: ">=2.17.0 <3.0.0"
diff --git a/example/pubspec.yaml b/example/pubspec.yaml
index 9a88feed..9975770b 100644
--- a/example/pubspec.yaml
+++ b/example/pubspec.yaml
@@ -5,19 +5,23 @@ documentation: https://hadrien-lejard.gitbook.io/chopper/
 #author: Hadrien Lejard <hadrien.lejard@gmail.com>
 
 environment:
-  sdk: '>=2.12.0 <3.0.0'
+  sdk: '>=2.17.0 <3.0.0'
 
 dependencies:
   chopper:
   json_annotation:
   built_value:
   analyzer:
+  http:
+  built_collection:
 
 dev_dependencies:
   build_runner:
   chopper_generator:
   json_serializable:
   built_value_generator:
+  dart_code_metrics: ^4.8.1
+  lints: ^2.0.0
 
 dependency_overrides:
  chopper: