diff --git a/samples/Domo.gs b/samples/Domo.gs
new file mode 100644
index 00000000..78dee77d
--- /dev/null
+++ b/samples/Domo.gs
@@ -0,0 +1,48 @@
+var CONSUMER_KEY = '60e79f78-696e-4977-b8af-22584dee428a';
+var CONSUMER_SECRET = '4bc8eb4d4db6a3b594177c334c4916799d463594c6771dae14a3644ecb3ebc01';
+
+/**
+ * Authorizes and makes a request to the Twitter Application Only API.
+ */
+function run() {
+  var service = getService();
+  if (service.hasAccess()) {
+    var url = 'https://api.domo.com/v1/users';
+    var response = UrlFetchApp.fetch(url, {
+      headers: {
+        Authorization: 'Bearer ' + service.getAccessToken()
+      }
+    });
+    var result = JSON.parse(response.getContentText());
+    Logger.log(JSON.stringify(result, null, 2));
+  } else {
+    Logger.log(service.getLastError());
+  }
+}
+
+/**
+ * Reset the authorization state, so that it can be re-tested.
+ */
+function reset() {
+  var service = getService();
+  service.reset();
+}
+
+/**
+ * Configures the service.
+ */
+function getService() {
+  return OAuth2.createService('Domo')
+      // Set the endpoint URL.
+      .setTokenUrl('https://api.domo.com/oauth/token')
+
+      // Set the consumer key and secret.
+      .setConsumerKey(CONSUMER_KEY)
+      .setConsumerSecret(CONSUMER_SECRET)
+
+      // Set the property store where authorized tokens should be persisted.
+      .setPropertyStore(PropertiesService.getScriptProperties())
+      
+      // Set the scope and additional headers required by the Domo API.
+      .setScope('data user');
+}
\ No newline at end of file
diff --git a/samples/Twitter.gs b/samples/Twitter.gs
new file mode 100644
index 00000000..4723d9d8
--- /dev/null
+++ b/samples/Twitter.gs
@@ -0,0 +1,45 @@
+var CONSUMER_KEY = 'tYRP6vIZuY8K7yzy2vBnnhRxB';
+var CONSUMER_SECRET = 'YoUMS8YOR9UxPEX0ZwYx5esV7rqHXRMnuqPV0xwDGkkAKqEu0G';
+
+/**
+ * Authorizes and makes a request to the Twitter Application Only API.
+ */
+function run() {
+  var service = getService();
+  if (service.hasAccess()) {
+    var url = 'https://api.twitter.com/1.1/application/rate_limit_status.json?resources=help,users,search,statuses';
+    var response = UrlFetchApp.fetch(url, {
+      headers: {
+        Authorization: 'Bearer ' + service.getAccessToken()
+      }
+    });
+    var result = JSON.parse(response.getContentText());
+    Logger.log(JSON.stringify(result, null, 2));
+  } else {
+    Logger.log(service.getLastError());
+  }
+}
+
+/**
+ * Reset the authorization state, so that it can be re-tested.
+ */
+function reset() {
+  var service = getService();
+  service.reset();
+}
+
+/**
+ * Configures the service.
+ */
+function getService() {
+  return OAuth2.createService('Twitter_Application_Only')
+      // Set the endpoint URL.
+      .setTokenUrl('https://api.twitter.com/oauth2/token')
+
+      // Set the consumer key and secret.
+      .setConsumerKey(CONSUMER_KEY)
+      .setConsumerSecret(CONSUMER_SECRET)
+
+      // Set the property store where authorized tokens should be persisted.
+      .setPropertyStore(PropertiesService.getScriptProperties());
+}
\ No newline at end of file
diff --git a/src/Service.gs b/src/Service.gs
index ed8a34de..0c729647 100644
--- a/src/Service.gs
+++ b/src/Service.gs
@@ -241,6 +241,38 @@ Service_.prototype.setExpirationMinutes = function(expirationMinutes) {
   return this;
 };
 
+/**
+ * Sets the consumer secret to use for grant flow authorization.
+ * @param {string} consummerSecret The consumer secret.
+ * @return {Service_} This service, for chaining.
+ */
+Service_.prototype.setConsumerSecret = function(consummerSecret) {
+  this.consumerSecret_ = consummerSecret;
+  return this;
+};
+
+/**
+ * Sets the consumer key to use for grant flow authorization.
+ * If not set the client ID will be used instead.
+ * @param {string} consumerKey This consumer key
+ * @return {Service_} This service, for chaining.
+ */
+Service_.prototype.setConsumerKey = function(consumerKey) {
+  this.consumerKey_ = consumerKey;
+  return this;
+};
+
+/**
+ * Sets the grant_type for an extension of grant flow authorization
+ * @param {string} grantType The extension grant type.
+ * @return {Service_} This service, for chaining.
+ */
+
+Service_.prototype.setGrantType = function(grantType) {
+  this.grantType_ = grantType;
+  return this;
+};
+
 /**
  * Gets the authorization URL. The first step in getting an OAuth2 token is to
  * have the user visit this URL and approve the authorization request. The
@@ -345,6 +377,13 @@ Service_.prototype.hasAccess = function() {
         this.lastError_ = e;
         return false;
       }
+    } else if (this.consumerSecret_){
+      try {
+        this.requestCCG_();
+      } catch (e) {
+        this.lastError_ = e;
+        return false;
+      }
     } else {
       return false;
     }
@@ -579,6 +618,38 @@ Service_.prototype.isExpired_ = function(token) {
   }
 };
 
+/**
+ * Uses Client Credentials Grant flow for getting an access token.
+ * https://tools.ietf.org/html/rfc6749#section-4.4
+ */
+Service_.prototype.requestCCG_ = function() {
+  validate_({
+    'Token URL': this.tokenUrl_
+  });
+  var headers = {
+    'Accept': this.tokenFormat_
+  };
+  if (this.tokenHeaders_) {
+    headers = _.extend(headers, this.tokenHeaders_);
+  }
+  var tokenPayload = {
+    scope: this.params_.scope,
+    grant_type: 'client_credentials'
+  };
+  if (this.tokenPayloadHandler_) {
+    tokenPayload = this.tokenPayloadHandler_(tokenPayload);
+    Logger.log('Token payload from tokenPayloadHandler: %s', JSON.stringify(tokenPayload));
+  }
+  var response = UrlFetchApp.fetch(this.tokenUrl_, {
+    method: 'post',
+    headers: headers,
+    payload: tokenPayload,
+    muteHttpExceptions: true
+  });
+  var token = this.getTokenFromResponse_(response);
+  this.saveToken_(token);
+};
+
 /**
  * Uses the service account flow to exchange a signed JSON Web Token (JWT) for an
  * access token.
@@ -643,3 +714,37 @@ Service_.prototype.createJwt_ = function() {
   var signature = Utilities.base64EncodeWebSafe(signatureBytes);
   return toSign + '.' + signature;
 };
+
+/**
+ * Uses Client Credentials Grant flow for getting an access token.
+ * https://tools.ietf.org/html/rfc6749#section-4.4
+ */
+Service_.prototype.requestCCG_ = function() {
+  validate_({
+    'Token URL': this.tokenUrl_
+  });
+  var consumerKey = this.consumerKey_ || this.clientId_;
+  var headers = {
+    'Accept': this.tokenFormat_,
+    'Authorization': 'Basic ' + Utilities.base64Encode(consumerKey + ':' + this.consumerSecret_)
+  };
+  if (this.tokenHeaders_) {
+    headers = _.extend(headers, this.tokenHeaders_);
+  }
+  var tokenPayload = {
+    scope: this.params_.scope,
+    grant_type: 'client_credentials' || this.grantType_
+  };
+  if (this.tokenPayloadHandler_) {
+    tokenPayload = this.tokenPayloadHandler_(tokenPayload);
+    Logger.log('Token payload from tokenPayloadHandler: %s', JSON.stringify(tokenPayload));
+  }
+  var response = UrlFetchApp.fetch(this.tokenUrl_, {
+    method: 'post',
+    headers: headers,
+    payload: tokenPayload,
+    muteHttpExceptions: true
+  });
+  var token = this.getTokenFromResponse_(response);
+  this.saveToken_(token);
+};
\ No newline at end of file