diff --git a/packages/rest/src/deserializer.ts b/packages/rest/src/deserializer.ts
new file mode 100644
index 000000000000..82c93c599d79
--- /dev/null
+++ b/packages/rest/src/deserializer.ts
@@ -0,0 +1,114 @@
+// Copyright IBM Corp. 2017,2018. All Rights Reserved.
+// Node module: @loopback/rest
+// This file is licensed under the MIT License.
+// License text available at https://opensource.org/licenses/MIT
+
+import * as assert from 'assert';
+import {ParameterObject} from '@loopback/openapi-spec';
+/**
+ * Simple deserializers for HTTP parameters
+ * @param val The value of the corresponding parameter type or a string
+ * @param param The Swagger parameter object
+ */
+// tslint:disable-next-line:no-any
+export function deserialize(val: any, param: ParameterObject): any {
+  if (param.in === 'body') {
+    param = getBodyDescriptor(param);
+  }
+  if (val == null) {
+    if (param.required) {
+      throw new Error(
+        `Value is not provided for required parameter ${param.name}`,
+      );
+    }
+    return val;
+  }
+  const type = param.type;
+  switch (type) {
+    case 'string':
+      if (typeof val === 'string') {
+        if (param.format === 'date' || param.format === 'date-time') {
+          return new Date(val);
+        }
+        return val;
+      }
+      throw new Error(
+        `Invalid value ${val} for parameter ${param.name}: ${type}`,
+      );
+    case 'number':
+    case 'integer':
+      let num: number = NaN;
+      if (typeof val === 'string') {
+        num = Number(val);
+      } else if (typeof val === 'number') {
+        num = val;
+      }
+      if (isNaN(num)) {
+        throw new Error(
+          `Invalid value ${val} for parameter ${param.name}: ${type}`,
+        );
+      }
+      if (type === 'integer' && !Number.isInteger(num)) {
+        throw new Error(
+          `Invalid value ${val} for parameter ${param.name}: ${type}`,
+        );
+      }
+      return num;
+    case 'boolean':
+      if (typeof val === 'boolean') return val;
+      if (val === 'false') return false;
+      else if (val === 'true') return true;
+      throw new Error(
+        `Invalid value ${val} for parameter ${param.name}: ${type}`,
+      );
+    case 'array':
+      let items = val;
+      if (typeof val === 'string') {
+        switch (param.collectionFormat) {
+          case 'ssv': // space separated values foo bar.
+            items = val.split(' ');
+            break;
+          case 'tsv': // tab separated values foo\tbar.
+            items = val.split('\t');
+            break;
+          case 'pipes': // pipe separated values foo|bar.
+            items = val.split('|');
+            break;
+          case 'csv': // comma separated values foo,bar.
+          default:
+            items = val.split(',');
+        }
+      }
+      if (Array.isArray(items)) {
+        return items.map(i => deserialize(i, getItemDescriptor(param)));
+      }
+      throw new Error(
+        `Invalid value ${val} for parameter ${param.name}: ${type}`,
+      );
+  }
+  return val;
+}
+
+/**
+ * Get the body descriptor
+ * @param param
+ */
+function getBodyDescriptor(param: ParameterObject): ParameterObject {
+  assert(param.in === 'body' && param.schema, 'Parameter location is not body');
+  return Object.assign(
+    {in: param.in, name: param.name, description: param.description},
+    param.schema,
+  );
+}
+
+/**
+ * Get the array item descriptor
+ * @param param
+ */
+function getItemDescriptor(param: ParameterObject): ParameterObject {
+  assert(param.type === 'array' && param.items, 'Parameter type is not array');
+  return Object.assign(
+    {in: param.in, name: param.name, description: param.description},
+    param.items,
+  );
+}
diff --git a/packages/rest/src/index.ts b/packages/rest/src/index.ts
index 339f47f08e43..5227ea3ed9f0 100644
--- a/packages/rest/src/index.ts
+++ b/packages/rest/src/index.ts
@@ -22,6 +22,7 @@ export * from './providers';
 import * as HttpErrors from 'http-errors';
 
 export * from './parser';
+export * from './deserializer';
 
 export {writeResultToResponse} from './writer';
 
diff --git a/packages/rest/src/parser.ts b/packages/rest/src/parser.ts
index 8c6696d4d022..4a78b5189fae 100644
--- a/packages/rest/src/parser.ts
+++ b/packages/rest/src/parser.ts
@@ -13,6 +13,8 @@ import {
   PathParameterValues,
 } from './internal-types';
 import {ResolvedRoute} from './router/routing-table';
+import {deserialize} from './deserializer';
+
 type HttpError = HttpErrors.HttpError;
 
 // tslint:disable-next-line:no-any
@@ -102,21 +104,23 @@ function buildOperationArguments(
       throw new Error('$ref parameters are not supported yet.');
     }
     const spec = paramSpec as ParameterObject;
+    // tslint:disable-next-line:no-any
+    const addArg = (val: any) => args.push(deserialize(val, spec));
     switch (spec.in) {
       case 'query':
-        args.push(request.query[spec.name]);
+        addArg(request.query[spec.name]);
         break;
       case 'path':
-        args.push(pathParams[spec.name]);
+        addArg(pathParams[spec.name]);
         break;
       case 'header':
-        args.push(request.headers[spec.name.toLowerCase()]);
+        addArg(request.headers[spec.name.toLowerCase()]);
         break;
       case 'formData':
-        args.push(body ? body[spec.name] : undefined);
+        addArg(body ? body[spec.name] : undefined);
         break;
       case 'body':
-        args.push(body);
+        addArg(body);
         break;
       default:
         throw new HttpErrors.NotImplemented(
diff --git a/packages/rest/test/unit/deserializer.test.ts b/packages/rest/test/unit/deserializer.test.ts
new file mode 100644
index 000000000000..cb69b48139f4
--- /dev/null
+++ b/packages/rest/test/unit/deserializer.test.ts
@@ -0,0 +1,225 @@
+// Copyright IBM Corp. 2017,2018. All Rights Reserved.
+// Node module: @loopback/rest
+// This file is licensed under the MIT License.
+// License text available at https://opensource.org/licenses/MIT
+
+import {deserialize} from '../..';
+import {expect} from '@loopback/testlab';
+import {ParameterObject} from '@loopback/openapi-spec';
+
+// tslint:disable:no-any
+describe('deserializer', () => {
+  it('converts number parameters', () => {
+    const param: ParameterObject = {
+      in: 'query',
+      name: 'balance',
+      type: 'number',
+    };
+    expectToDeserialize(param, [0, 1.5, '10', '2.5'], [0, 1.5, 10, 2.5]);
+    expectToDeserializeNullOrUndefined(param);
+  });
+
+  it('reports errors for invalid number parameters', () => {
+    const param: ParameterObject = {
+      in: 'query',
+      name: 'balance',
+      type: 'number',
+    };
+    expectToFail(
+      param,
+      ['a', 'a1', 'true', true, false, {}, new Date()],
+      /Invalid value .* for parameter balance\: number/,
+    );
+  });
+
+  it('converts integer parameters', () => {
+    const param: ParameterObject = {
+      in: 'query',
+      name: 'id',
+      type: 'integer',
+    };
+    expectToDeserialize(param, [0, -1, '10', '-5'], [0, -1, 10, -5]);
+  });
+
+  it('reports erros for invalid integer parameters', () => {
+    const param: ParameterObject = {
+      in: 'query',
+      name: 'id',
+      type: 'integer',
+    };
+    expectToFail(
+      param,
+      ['a', 'a1', 'true', {}, 1.5, '-2.5'],
+      /Invalid value .* for parameter id\: integer/,
+    );
+  });
+
+  it('converts boolean parameters', () => {
+    const param: ParameterObject = {
+      in: 'query',
+      name: 'vip',
+      type: 'boolean',
+    };
+    expectToDeserialize(
+      param,
+      [true, false, 'true', 'false'],
+      [true, false, true, false],
+    );
+    expectToDeserializeNullOrUndefined(param);
+  });
+
+  it('reports errors for invalid boolean parameters', () => {
+    const param: ParameterObject = {
+      in: 'query',
+      name: 'vip',
+      type: 'boolean',
+    };
+    expectToFail(
+      param,
+      ['a', 'a1', {}, 1.5, 0, 1, -10],
+      /Invalid value .* for parameter vip\: boolean/,
+    );
+  });
+
+  it('converts string parameters', () => {
+    const param: ParameterObject = {
+      in: 'query',
+      name: 'name',
+      type: 'string',
+    };
+    expectToDeserialize(param, ['', 'A'], ['', 'A']);
+    expectToDeserializeNullOrUndefined(param);
+  });
+
+  it('reports errors for invalid string parameters', () => {
+    const param: ParameterObject = {
+      in: 'query',
+      name: 'name',
+      type: 'string',
+    };
+    expectToFail(
+      param,
+      [true, false, 0, -1, 2.5, {}, new Date()],
+      /Invalid value .* for parameter name\: string/,
+    );
+  });
+
+  it('converts date parameters', () => {
+    const param: ParameterObject = {
+      in: 'query',
+      name: 'date',
+      type: 'string',
+      format: 'date',
+    };
+    const date = new Date();
+    expectToDeserialize(param, [date.toJSON()], [date]);
+  });
+
+  describe('string[]', () => {
+    it('converts csv format', () => {
+      const param: ParameterObject = {
+        in: 'query',
+        name: 'nums',
+        type: 'array',
+        collectionFormat: 'csv',
+        items: {
+          type: 'string',
+        },
+      };
+      expectToDeserialize(
+        param,
+        ['1,2,3', 'ab,c'],
+        [['1', '2', '3'], ['ab', 'c']],
+      );
+    });
+
+    it('converts ssv format', () => {
+      const param: ParameterObject = {
+        in: 'query',
+        name: 'nums',
+        type: 'array',
+        collectionFormat: 'ssv',
+        items: {
+          type: 'string',
+        },
+      };
+      expectToDeserialize(
+        param,
+        ['1 2 3', 'ab c'],
+        [['1', '2', '3'], ['ab', 'c']],
+      );
+    });
+
+    it('converts pipes format', () => {
+      const param: ParameterObject = {
+        in: 'query',
+        name: 'nums',
+        type: 'array',
+        collectionFormat: 'pipes',
+        items: {
+          type: 'string',
+        },
+      };
+      expectToDeserialize(
+        param,
+        ['1|2|3', 'ab|c'],
+        [['1', '2', '3'], ['ab', 'c']],
+      );
+    });
+
+    it('converts tsv format', () => {
+      const param: ParameterObject = {
+        in: 'query',
+        name: 'nums',
+        type: 'array',
+        collectionFormat: 'tsv',
+        items: {
+          type: 'string',
+        },
+      };
+      expectToDeserialize(
+        param,
+        ['1\t2\t3', 'ab\tc'],
+        [['1', '2', '3'], ['ab', 'c']],
+      );
+    });
+  });
+
+  describe('number[]', () => {
+    it('converts csv format', () => {
+      const param: ParameterObject = {
+        in: 'query',
+        name: 'nums',
+        type: 'array',
+        collectionFormat: 'csv',
+        items: {
+          type: 'number',
+        },
+      };
+      expectToDeserialize(param, ['1,2,3', '-10,2.5'], [[1, 2, 3], [-10, 2.5]]);
+    });
+  });
+
+  function expectToDeserialize(
+    param: ParameterObject,
+    source: any[],
+    target: any[],
+  ) {
+    expect(source.map(i => deserialize(i, param))).to.eql(target);
+  }
+
+  function expectToDeserializeNullOrUndefined(param: ParameterObject) {
+    expect(deserialize(null, param)).to.be.null();
+    expect(deserialize(undefined, param)).to.be.undefined();
+  }
+
+  function expectToFail(
+    param: ParameterObject,
+    source: any[],
+    reason: string | RegExp,
+  ) {
+    for (const i of source) {
+      expect(() => deserialize(i, param)).to.throw(reason);
+    }
+  }
+});