diff --git a/.jshintrc b/.jshintrc
index c9f2f2d..bba5b74 100644
--- a/.jshintrc
+++ b/.jshintrc
@@ -10,6 +10,7 @@
     "curly": true,
     "eqeqeq": true,
     "expr": true,
+    "node": true,
 
     "predef": [
         "describe",
diff --git a/README.md b/README.md
index a79ea23..e58b286 100644
--- a/README.md
+++ b/README.md
@@ -22,6 +22,8 @@ Possible options values:
   * **refreshToken** _(Required)_ Refresh token for an user
   * **accessToken** _(Optional)_ initial access token. If not set, a new one will be generated
   * **timeout** _(Optional)_ TTL in **seconds**
+  * **customHeaders** _(Optional)_ custom headers to send during token generation request [yahoo requires `Authorization: Basic Base64(clientId:clientSecret)` ](https://developer.yahoo.com/oauth2/guide/flows_authcode/#step-5-exchange-refresh-token-for-new-access-token)
+  * **customParams** _(Optional)_ custom payload to send on getToken request [yahoo requires redirect_uri to be specified](https://developer.yahoo.com/oauth2/guide/flows_authcode/#step-5-exchange-refresh-token-for-new-access-token)
 
 See [https://developers.google.com/accounts/docs/OAuth2WebServer#offline]() for generating the required credentials
 
@@ -58,7 +60,13 @@ If a new token value has been set, `'token'` event is emitted.
         user: "user@gmail.com",
         clientId: "{Client ID}",
         clientSecret: "{Client Secret}",
-        refreshToken: "{User Refresh Token}"
+        refreshToken: "{User Refresh Token}",
+        customHeaders: {
+          "HeaderName": "HeaderValue"
+        },
+        customPayload: {
+          "payloadParamName": "payloadValue"
+        }
     });
 
     // SMTP/IMAP
diff --git a/package.json b/package.json
index ab9b5d1..7153627 100644
--- a/package.json
+++ b/package.json
@@ -13,6 +13,7 @@
   "keywords": [
     "XOAUTH",
     "XOAUTH2",
+    "Yahoo",
     "GMail",
     "SMTP",
     "IMAP"
diff --git a/src/xoauth2.js b/src/xoauth2.js
index f26588a..78b5a88 100644
--- a/src/xoauth2.js
+++ b/src/xoauth2.js
@@ -45,6 +45,8 @@ function XOAuth2Generator(options) {
     this.options = options || {};
 
     this.options.accessUrl = this.options.accessUrl || 'https://accounts.google.com/o/oauth2/token';
+    this.options.customHeaders = this.options.customHeaders || {};
+    this.options.customParams = this.options.customParams || {};
 
     this.token = this.options.accessToken && this.buildXOAuth2Token(this.options.accessToken) || false;
     this.accessToken = this.token && this.options.accessToken || false;
@@ -98,10 +100,15 @@ XOAuth2Generator.prototype.generateToken = function(callback) {
             client_secret: this.options.clientSecret || '',
             refresh_token: this.options.refreshToken,
             grant_type: 'refresh_token'
-        },
-        payload = querystring.stringify(urlOptions);
+        };
 
-    postRequest(this.options.accessUrl, payload, (function(error, response, body) {
+    for (var param in this.options.customParams) {
+        urlOptions[param] = this.options.customParams[param];
+    }
+
+    var payload = querystring.stringify(urlOptions);
+    var self = this;
+    postRequest.call(this, this.options.accessUrl, payload, function (error, response, body) {
         var data;
 
         if (error) {
@@ -123,12 +130,12 @@ XOAuth2Generator.prototype.generateToken = function(callback) {
         }
 
         if (data.access_token) {
-            this.updateToken(data.access_token, data.expires_in);
-            return callback(null, this.token, this.accessToken);
+            self.updateToken(data.access_token, data.expires_in);
+            return callback(null, self.token, self.accessToken);
         }
 
         return callback(new Error('No access token'));
-    }).bind(this));
+    });
 };
 
 /**
@@ -162,7 +169,8 @@ XOAuth2Generator.prototype.buildXOAuth2Token = function(accessToken) {
 function postRequest(url, payload, callback) {
     var options = urllib.parse(url),
         finished = false,
-        response = null;
+        response = null,
+        req;
 
     options.method = 'POST';
 
@@ -183,7 +191,7 @@ function postRequest(url, payload, callback) {
         callback.apply(null, arguments);
     };
 
-    var req = (options.protocol === 'https:' ? https : http).request(options, function(res) {
+    req = (options.protocol === 'https:' ? https : http).request(options, function(res) {
         response = res;
         var data = [];
         var datalen = 0;
@@ -211,5 +219,9 @@ function postRequest(url, payload, callback) {
         req.setHeader('Content-Length', typeof payload === 'string' ? Buffer.byteLength(payload) : payload.length);
     }
 
+    for (var customHeaderName in this.options.customHeaders) {
+      req.setHeader(customHeaderName, this.options.customHeaders[customHeaderName]);
+    }
+
     req.end(payload);
-}
\ No newline at end of file
+}