diff --git a/README.md b/README.md
index 64c7895..87b3700 100644
--- a/README.md
+++ b/README.md
@@ -1,29 +1,29 @@
 node-gapitoken
 ==============
 
-Node.js module for Google API service account authorization (Server to Server flow). 
+Node.js module for Google-compatible API service account authorization (Server to Server flow).
 
 Installation
 ------------
 
-	npm install gapitoken
-	
+	npm install gapitoken-generic
+
 Usage
 -----
 
-    var GAPI = require('gapitoken');
- 
+    var GAPI = require('gapitoken-generic');
+
     var gapi = new GAPI({
         iss: 'service account email address from Google API console',
         scope: 'space delimited list of requested scopes',
         keyFile: 'path to private_key.pem'
     }, function(err) {
        if (err) { return console.log(err); }
- 
+
        gapi.getToken(function(err, token) {
            if (err) { return console.log(err); }
            console.log(token);
-       });     
+       });
     });
 
 Another option is to pass the private key as a string
@@ -45,10 +45,10 @@ Another option is to pass the private key as a string
        gapi.getToken(function(err, token) {
            if (err) { return console.log(err); }
            console.log(token);
-       });     
+       });
     });
 
-    
+
 * for using node-gapitoken to access Google Cloud Storage see https://github.com/bsphere/node-gcs
 
 Creating a Private key file
@@ -62,4 +62,4 @@ Creating a Private key file
 
 NOTE: You must set a passphrase for the .pem file
 
-4) Remove the passphrase from the .pem file: `openssl rsa -in key.pem -out key.pem`
\ No newline at end of file
+4) Remove the passphrase from the .pem file: `openssl rsa -in key.pem -out key.pem`
diff --git a/gapitoken.js b/gapitoken.js
index 25259b9..f7e9592 100644
--- a/gapitoken.js
+++ b/gapitoken.js
@@ -10,22 +10,27 @@ var GAPI = function(options, callback) {
 	this.scope = options.scope;
 	this.sub = options.sub;
 	this.prn = options.prn;
-	
-    if (options.keyFile) {
-        var self = this;
-        process.nextTick(function() {
-            fs.readFile(options.keyFile, function(err, res) {
-                if (err) { return callback(err); }
-                self.key = res;
-                callback();
-            });        
-        });
-    } else if (options.key) {
-        this.key = options.key;
-        process.nextTick(callback);
-    } else {
-        callback(new Error("Missing key, key or keyFile option must be provided!"));
-    }
+	this.aud = options.aud || 'https://accounts.google.com/o/oauth2/token';
+	this.host = options.host || 'accounts.google.com';
+	this.path = options.path || '/o/oauth2/token';
+	this.port = options.port;
+	this.grant = options.grant || 'urn:ietf:params:oauth:grant-type:jwt-bearer';
+
+	if (options.keyFile) {
+      var self = this;
+      process.nextTick(function() {
+          fs.readFile(options.keyFile, function(err, res) {
+              if (err) { return callback(err); }
+              self.key = res;
+              callback();
+          });
+      });
+  } else if (options.key) {
+      this.key = options.key;
+      process.nextTick(callback);
+  } else {
+      callback(new Error("Missing key, key or keyFile option must be provided!"));
+  }
 };
 
 GAPI.prototype.getToken = function(callback) {
@@ -33,7 +38,7 @@ GAPI.prototype.getToken = function(callback) {
         callback(null, this.token);
     } else {
         this.getAccessToken(callback);
-    }	
+    }
 };
 
 GAPI.prototype.getAccessToken = function(callback) {
@@ -42,7 +47,7 @@ GAPI.prototype.getAccessToken = function(callback) {
     var payload = {
         iss: this.iss,
         scope: this.scope,
-        aud: 'https://accounts.google.com/o/oauth2/token',
+        aud: this.aud,
         exp: iat + 3600,
         iat: iat
     };
@@ -59,16 +64,20 @@ GAPI.prototype.getAccessToken = function(callback) {
         secret: this.key
     });
 
-    var post_data = 'grant_type=urn%3Aietf%3Aparams%3Aoauth%3Agrant-type%3Ajwt-bearer&assertion=' + signedJWT;
+    var post_data = 'grant_type=' + encodeURIComponent(this.grant) + '&assertion=' + signedJWT;
     var post_options = {
-        host: 'accounts.google.com',
-        path: '/o/oauth2/token',
+        host: this.host,
+        path: this.path,
         method: 'POST',
         headers: {
             'Content-Type': 'application/x-www-form-urlencoded'
         }
     };
 
+		if (this.port) {
+			post_options.port = this.port;
+		}
+
     var self = this;
     var post_req = https.request(post_options, function(res) {
         var d = '';
@@ -100,7 +109,7 @@ GAPI.prototype.getAccessToken = function(callback) {
     });
 
     post_req.write(post_data);
-    post_req.end();	
+    post_req.end();
 };
 
 module.exports = GAPI;