diff --git a/extensions/amazon-lambda/common-deployment/pom.xml b/extensions/amazon-lambda/common-deployment/pom.xml
index 6fa00eea9b452..0fd84942a5f72 100644
--- a/extensions/amazon-lambda/common-deployment/pom.xml
+++ b/extensions/amazon-lambda/common-deployment/pom.xml
@@ -61,9 +61,6 @@
                                     <version>${project.version}</version>
                                 </path>
                             </annotationProcessorPaths>
-                            <compilerArgs>
-                                <arg>-AlegacyConfigRoot=true</arg>
-                            </compilerArgs>
                         </configuration>
                     </execution>
                 </executions>
diff --git a/extensions/amazon-lambda/common-deployment/src/main/java/io/quarkus/amazon/lambda/deployment/DevServicesLambdaProcessor.java b/extensions/amazon-lambda/common-deployment/src/main/java/io/quarkus/amazon/lambda/deployment/DevServicesLambdaProcessor.java
index c30f5e707a21a..84c3f128445fb 100644
--- a/extensions/amazon-lambda/common-deployment/src/main/java/io/quarkus/amazon/lambda/deployment/DevServicesLambdaProcessor.java
+++ b/extensions/amazon-lambda/common-deployment/src/main/java/io/quarkus/amazon/lambda/deployment/DevServicesLambdaProcessor.java
@@ -63,7 +63,7 @@ public void startEventServer(LaunchModeBuildItem launchMode,
             return;
         if (legacyTestingEnabled())
             return;
-        if (!config.mockEventServer.enabled) {
+        if (!config.mockEventServer().enabled()) {
             return;
         }
         if (server != null) {
@@ -77,8 +77,8 @@ public void startEventServer(LaunchModeBuildItem launchMode,
         }
 
         server = supplier.get();
-        int port = launchMode.getLaunchMode() == LaunchMode.TEST ? config.mockEventServer.testPort
-                : config.mockEventServer.devPort;
+        int port = launchMode.getLaunchMode() == LaunchMode.TEST ? config.mockEventServer().testPort()
+                : config.mockEventServer().devPort();
         startMode = launchMode.getLaunchMode();
         server.start(port);
         int actualPort = server.getPort();
diff --git a/extensions/amazon-lambda/common-deployment/src/main/java/io/quarkus/amazon/lambda/deployment/LambdaConfig.java b/extensions/amazon-lambda/common-deployment/src/main/java/io/quarkus/amazon/lambda/deployment/LambdaConfig.java
index e9dcc8e4c3e61..36c15e3e3a77e 100644
--- a/extensions/amazon-lambda/common-deployment/src/main/java/io/quarkus/amazon/lambda/deployment/LambdaConfig.java
+++ b/extensions/amazon-lambda/common-deployment/src/main/java/io/quarkus/amazon/lambda/deployment/LambdaConfig.java
@@ -2,13 +2,15 @@
 
 import io.quarkus.runtime.annotations.ConfigPhase;
 import io.quarkus.runtime.annotations.ConfigRoot;
+import io.smallrye.config.ConfigMapping;
 
 @ConfigRoot(phase = ConfigPhase.BUILD_TIME)
-public class LambdaConfig {
+@ConfigMapping(prefix = "quarkus.lambda")
+public interface LambdaConfig {
 
     /**
      * Configuration for the mock event server that is run
      * in dev mode and test mode
      */
-    MockEventServerConfig mockEventServer;
+    MockEventServerConfig mockEventServer();
 }
diff --git a/extensions/amazon-lambda/common-deployment/src/main/java/io/quarkus/amazon/lambda/deployment/MockEventServerConfig.java b/extensions/amazon-lambda/common-deployment/src/main/java/io/quarkus/amazon/lambda/deployment/MockEventServerConfig.java
index 85cde4c70a1fb..c2aa666e9810f 100644
--- a/extensions/amazon-lambda/common-deployment/src/main/java/io/quarkus/amazon/lambda/deployment/MockEventServerConfig.java
+++ b/extensions/amazon-lambda/common-deployment/src/main/java/io/quarkus/amazon/lambda/deployment/MockEventServerConfig.java
@@ -1,29 +1,27 @@
 package io.quarkus.amazon.lambda.deployment;
 
-import io.quarkus.runtime.annotations.ConfigGroup;
-import io.quarkus.runtime.annotations.ConfigItem;
+import io.smallrye.config.WithDefault;
 
 /**
  * Configuration for the mock event server that is run
  * in dev mode and test mode
  */
-@ConfigGroup
-public class MockEventServerConfig {
+public interface MockEventServerConfig {
     /**
      * Setting to true will start event server even if quarkus.devservices.enabled=false
      */
-    @ConfigItem(defaultValue = "true")
-    public boolean enabled;
+    @WithDefault("true")
+    boolean enabled();
 
     /**
      * Port to access mock event server in dev mode
      */
-    @ConfigItem(defaultValue = "8080")
-    public int devPort;
+    @WithDefault("8080")
+    int devPort();
 
     /**
      * Port to access mock event server in dev mode
      */
-    @ConfigItem(defaultValue = "8081")
-    public int testPort;
+    @WithDefault("8081")
+    int testPort();
 }
diff --git a/extensions/amazon-lambda/common-runtime/pom.xml b/extensions/amazon-lambda/common-runtime/pom.xml
index eb8a8bab3501b..36b98ed34d715 100644
--- a/extensions/amazon-lambda/common-runtime/pom.xml
+++ b/extensions/amazon-lambda/common-runtime/pom.xml
@@ -72,9 +72,6 @@
                                     <version>${project.version}</version>
                                 </path>
                             </annotationProcessorPaths>
-                            <compilerArgs>
-                                <arg>-AlegacyConfigRoot=true</arg>
-                            </compilerArgs>
                         </configuration>
                     </execution>
                 </executions>
diff --git a/extensions/amazon-lambda/deployment/src/main/java/io/quarkus/amazon/lambda/deployment/AmazonLambdaProcessor.java b/extensions/amazon-lambda/deployment/src/main/java/io/quarkus/amazon/lambda/deployment/AmazonLambdaProcessor.java
index d7b631b826e24..6ce046aa7da98 100644
--- a/extensions/amazon-lambda/deployment/src/main/java/io/quarkus/amazon/lambda/deployment/AmazonLambdaProcessor.java
+++ b/extensions/amazon-lambda/deployment/src/main/java/io/quarkus/amazon/lambda/deployment/AmazonLambdaProcessor.java
@@ -333,7 +333,7 @@ void startPoolLoopDevOrTest(AmazonLambdaRecorder recorder,
     void recordExpectedExceptions(LambdaBuildTimeConfig config,
             BuildProducer<ReflectiveClassBuildItem> registerForReflection,
             AmazonLambdaStaticRecorder recorder) {
-        Set<Class<?>> classes = config.expectedExceptions.map(Set::copyOf).orElseGet(Set::of);
+        Set<Class<?>> classes = config.expectedExceptions().map(Set::copyOf).orElseGet(Set::of);
         classes.stream()
                 .map(clazz -> ReflectiveClassBuildItem.builder(clazz).constructors(false)
                         .reason(getClass().getName() + " expectedExceptions")
diff --git a/extensions/amazon-lambda/runtime/pom.xml b/extensions/amazon-lambda/runtime/pom.xml
index 0a565e1dbe5e1..e12340e996247 100644
--- a/extensions/amazon-lambda/runtime/pom.xml
+++ b/extensions/amazon-lambda/runtime/pom.xml
@@ -51,9 +51,6 @@
                                     <version>${project.version}</version>
                                 </path>
                             </annotationProcessorPaths>
-                            <compilerArgs>
-                                <arg>-AlegacyConfigRoot=true</arg>
-                            </compilerArgs>
                         </configuration>
                     </execution>
                 </executions>
diff --git a/extensions/amazon-lambda/runtime/src/main/java/io/quarkus/amazon/lambda/runtime/AmazonLambdaRecorder.java b/extensions/amazon-lambda/runtime/src/main/java/io/quarkus/amazon/lambda/runtime/AmazonLambdaRecorder.java
index 49dc6d9d92a2b..6ff6371ae775b 100644
--- a/extensions/amazon-lambda/runtime/src/main/java/io/quarkus/amazon/lambda/runtime/AmazonLambdaRecorder.java
+++ b/extensions/amazon-lambda/runtime/src/main/java/io/quarkus/amazon/lambda/runtime/AmazonLambdaRecorder.java
@@ -120,12 +120,12 @@ public void chooseHandlerClass(List<Class<? extends RequestHandler<?, ?>>> unnam
 
         Class<? extends RequestHandler<?, ?>> handlerClass = null;
         Class<? extends RequestStreamHandler> handlerStreamClass = null;
-        if (config.handler.isPresent()) {
-            handlerClass = namedHandlerClasses.get(config.handler.get());
-            handlerStreamClass = namedStreamHandlerClasses.get(config.handler.get());
+        if (config.handler().isPresent()) {
+            handlerClass = namedHandlerClasses.get(config.handler().get());
+            handlerStreamClass = namedStreamHandlerClasses.get(config.handler().get());
 
             if (handlerClass == null && handlerStreamClass == null) {
-                String errorMessage = "Unable to find handler class with name " + config.handler.get()
+                String errorMessage = "Unable to find handler class with name " + config.handler().get()
                         + " make sure there is a handler class in the deployment with the correct @Named annotation";
                 throw new RuntimeException(errorMessage);
             }
diff --git a/extensions/amazon-lambda/runtime/src/main/java/io/quarkus/amazon/lambda/runtime/LambdaBuildTimeConfig.java b/extensions/amazon-lambda/runtime/src/main/java/io/quarkus/amazon/lambda/runtime/LambdaBuildTimeConfig.java
index 4a035af4fb7ee..5bf355cef4911 100644
--- a/extensions/amazon-lambda/runtime/src/main/java/io/quarkus/amazon/lambda/runtime/LambdaBuildTimeConfig.java
+++ b/extensions/amazon-lambda/runtime/src/main/java/io/quarkus/amazon/lambda/runtime/LambdaBuildTimeConfig.java
@@ -3,12 +3,13 @@
 import java.util.List;
 import java.util.Optional;
 
-import io.quarkus.runtime.annotations.ConfigItem;
 import io.quarkus.runtime.annotations.ConfigPhase;
 import io.quarkus.runtime.annotations.ConfigRoot;
+import io.smallrye.config.ConfigMapping;
 
-@ConfigRoot(name = "lambda", phase = ConfigPhase.BUILD_AND_RUN_TIME_FIXED)
-public class LambdaBuildTimeConfig {
+@ConfigRoot(phase = ConfigPhase.BUILD_AND_RUN_TIME_FIXED)
+@ConfigMapping(prefix = "quarkus.lambda")
+public interface LambdaBuildTimeConfig {
 
     /**
      * The exception classes expected to be thrown by the handler.
@@ -17,6 +18,5 @@ public class LambdaBuildTimeConfig {
      * but will otherwise be handled normally by the lambda runtime. This is useful for avoiding unnecessary
      * stack traces while preserving the ability to log unexpected exceptions.
      */
-    @ConfigItem
-    public Optional<List<Class<?>>> expectedExceptions;
+    Optional<List<Class<?>>> expectedExceptions();
 }
diff --git a/extensions/amazon-lambda/runtime/src/main/java/io/quarkus/amazon/lambda/runtime/LambdaConfig.java b/extensions/amazon-lambda/runtime/src/main/java/io/quarkus/amazon/lambda/runtime/LambdaConfig.java
index 8335b3f3d3a08..0aceb7a4f08ef 100644
--- a/extensions/amazon-lambda/runtime/src/main/java/io/quarkus/amazon/lambda/runtime/LambdaConfig.java
+++ b/extensions/amazon-lambda/runtime/src/main/java/io/quarkus/amazon/lambda/runtime/LambdaConfig.java
@@ -2,12 +2,13 @@
 
 import java.util.Optional;
 
-import io.quarkus.runtime.annotations.ConfigItem;
 import io.quarkus.runtime.annotations.ConfigPhase;
 import io.quarkus.runtime.annotations.ConfigRoot;
+import io.smallrye.config.ConfigMapping;
 
 @ConfigRoot(phase = ConfigPhase.RUN_TIME)
-public class LambdaConfig {
+@ConfigMapping(prefix = "quarkus.lambda")
+public interface LambdaConfig {
 
     /**
      * The handler name. Handler names are specified on handler classes using the {@link @jakarta.inject.Named} annotation.
@@ -18,6 +19,5 @@ public class LambdaConfig {
      * then the named handler will be used.
      *
      */
-    @ConfigItem
-    public Optional<String> handler;
+    Optional<String> handler();
 }