diff --git a/amplifyjs/amplifyjs-tests.ts b/amplifyjs/amplifyjs-tests.ts
index c26955348..a104d4a7c 100644
--- a/amplifyjs/amplifyjs-tests.ts
+++ b/amplifyjs/amplifyjs-tests.ts
@@ -176,8 +176,7 @@ amplify.request("twitter-mentions", { user: "amplifyjs" });
 
 //Example:
 
-amplify.request.decoders.appEnvelope =
-function (data, status, xhr, success, error) {
+var appEnvelopeDecoder: amplifyDecoder = function (data, status, xhr, success, error) {
     if (data.status === "success") {
         success(data.data);
     } else if (data.status === "fail" || data.status === "error") {
@@ -187,6 +186,17 @@ function (data, status, xhr, success, error) {
     }
 };
 
+//a new decoder can be added to the amplifyDecoders interface
+interface amplifyDecoders {
+    appEnvelope: amplifyDecoder;
+}
+
+amplify.request.decoders.appEnvelope = appEnvelopeDecoder;
+
+//but you can also just add it via an index
+amplify.request.decoders['appEnvelopeStr'] = appEnvelopeDecoder;
+
+
 amplify.request.define("decoderExample", "ajax", {
     url: "/myAjaxUrl",
     type: "POST",
diff --git a/amplifyjs/amplifyjs.d.ts b/amplifyjs/amplifyjs.d.ts
index c8de7260a..a918b7c73 100644
--- a/amplifyjs/amplifyjs.d.ts
+++ b/amplifyjs/amplifyjs.d.ts
@@ -1,3 +1,5 @@
+/// <reference path="../jquery/jquery.d.ts" />
+
 // Type definitions for AmplifyJs 1.1.0
 // Project: http://amplifyjs.com/
 // Definitions by: Jonas Eriksson <https://github.com/joeriks/>
@@ -6,8 +8,28 @@
 interface amplifyRequestSettings {
     resourceId: string;
     data?: any;
-    success?: Function;
-    error?: Function;
+    success?: (...args: any[]) => void;
+    error?: (...args: any[]) => void;
+}
+
+interface amplifyDecoder {
+    (   
+        data?: any, 
+        status?: string, 
+        xhr?: JQueryXHR, 
+        success?: (...args: any[]) => void,
+        error?: (...args: any[]) => void
+    ): void
+}
+
+interface amplifyDecoders {
+    [decoderName: string]: amplifyDecoder;
+    jsSend: amplifyDecoder;
+}
+
+interface amplifyAjaxSettings extends JQueryAjaxSettings  {
+    cache?: any;
+    decoder?: any /* string or amplifyDecoder */;
 }
 
 interface amplifyRequest {
@@ -39,7 +61,7 @@ interface amplifyRequest {
     *   cache: See the cache section for more details.
     *   decoder: See the decoder section for more details.
     */
-    define(resourceId: string, requestType: string, settings?: any): void;
+    define(resourceId: string, requestType: string, settings?: amplifyAjaxSettings): void;
 
     /***
     * Define a custom request.
@@ -50,9 +72,9 @@ interface amplifyRequest {
     *   success: Callback to invoke on success.
     *   error: Callback to invoke on error.
     */
-    define(resourceId: string, resource: Function): void;
-	
-    decoders: any;
+    define(resourceId: string, resource: (settings: amplifyRequestSettings) => void): void;
+    
+    decoders: amplifyDecoders;
     cache: any;
 }