diff --git a/appengine/cloudtasks/createTask.js b/appengine/cloudtasks/createTask.js
index 83cf0af35f..d329a6e62e 100644
--- a/appengine/cloudtasks/createTask.js
+++ b/appengine/cloudtasks/createTask.js
@@ -15,7 +15,7 @@
 
 'use strict';
 
-const google = require('googleapis').google;
+const {google} = require('googleapis');
 const cloudtasks = google.cloudtasks('v2beta2');
 
 /**
@@ -23,7 +23,9 @@ const cloudtasks = google.cloudtasks('v2beta2');
  */
 function createTask (project, location, queue, options) {
   // [START cloud_tasks_appengine_create_task]
-  authorize((authClient) => {
+  google.auth.getClient({
+    scopes: ['https://www.googleapis.com/auth/cloud-platform']
+  }).then(authClient => {
     const task = {
       app_engine_http_request: {
         http_method: 'POST',
@@ -48,31 +50,11 @@ function createTask (project, location, queue, options) {
     };
 
     console.log('Sending task %j', task);
-
-    cloudtasks.projects.locations.queues.tasks.create(request, (err, response) => {
-      if (err) {
-        console.error(err);
-        return;
-      }
-
-      console.log('Created task.', response.name);
-      console.log(JSON.stringify(response, null, 2));
-    });
-  });
-
-  function authorize (callback) {
-    google.auth.getApplicationDefault(function (err, authClient) {
-      if (err) {
-        console.error('authentication failed: ', err);
-        return;
-      }
-      if (authClient.createScopedRequired && authClient.createScopedRequired()) {
-        var scopes = ['https://www.googleapis.com/auth/cloud-platform'];
-        authClient = authClient.createScoped(scopes);
-      }
-      callback(authClient);
-    });
-  }
+    return cloudtasks.projects.locations.queues.tasks.create(request);
+  }).then(response => {
+    console.log('Created task.', response.name);
+    console.log(JSON.stringify(response, null, 2));
+  }).catch(console.error);
   // [END cloud_tasks_appengine_create_task]
 }
 
@@ -121,9 +103,7 @@ const cli = require(`yargs`)
 
 if (module === require.main) {
   const opts = cli.help().parse(process.argv.slice(2));
-
   process.env.GCLOUD_PROJECT = opts.project;
-
   createTask(opts.project, opts.location, opts.queue, opts);
 }
 
diff --git a/appengine/cloudtasks/package.json b/appengine/cloudtasks/package.json
index 294f44abd7..812536ff3f 100644
--- a/appengine/cloudtasks/package.json
+++ b/appengine/cloudtasks/package.json
@@ -20,7 +20,7 @@
   "dependencies": {
     "body-parser": "1.18.2",
     "express": "4.16.2",
-    "googleapis": "27.0.0",
+    "googleapis": "29.0.0",
     "yargs": "11.0.0"
   },
   "devDependencies": {
diff --git a/appengine/loopback/server/boot/root.js b/appengine/loopback/server/boot/root.js
index 6adce90ad3..65dfc96cbb 100644
--- a/appengine/loopback/server/boot/root.js
+++ b/appengine/loopback/server/boot/root.js
@@ -2,7 +2,7 @@
 
 module.exports = function(server) {
   // Install a `/` route that returns server status
-  var router = server.loopback.Router();
+  const router = server.loopback.Router();
   router.get('/', server.loopback.status());
   server.use(router);
 };
diff --git a/circle.yml b/circle.yml
index c2778d3afb..455873585e 100644
--- a/circle.yml
+++ b/circle.yml
@@ -18,7 +18,7 @@
 
 machine:
   node:
-    version: 8.11.1
+    version: 6.14.2
 
 # Use for broader build-related configuration
 general:
diff --git a/cloudtasks/package.json b/cloudtasks/package.json
index 6aa99f5e84..925e114176 100644
--- a/cloudtasks/package.json
+++ b/cloudtasks/package.json
@@ -15,7 +15,7 @@
     "test": "repo-tools test run --cmd npm -- run system-test"
   },
   "dependencies": {
-    "googleapis": "27.0.0",
+    "googleapis": "29.0.0",
     "yargs": "11.0.0"
   },
   "devDependencies": {
diff --git a/cloudtasks/tasks.js b/cloudtasks/tasks.js
index de3708ade7..dfd67d34be 100644
--- a/cloudtasks/tasks.js
+++ b/cloudtasks/tasks.js
@@ -17,7 +17,7 @@
 
 function createTask (project, location, queue) {
   // [START cloud_tasks_create_task]
-  const google = require('googleapis').google;
+  const {google} = require('googleapis');
   const cloudtasks = google.cloudtasks('v2beta2');
 
   /**
@@ -27,56 +27,42 @@ function createTask (project, location, queue) {
   // const location = 'Location of queue, e.g. us-central1';
   // const queue = 'Queue ID, e.g. queue-1';
 
-  authorize((authClient) => {
-    // Schedule the task for 2 minutes from now
-    const scheduleTime = new Date();
-    scheduleTime.setUTCMinutes(scheduleTime.getUTCMinutes() + 2);
-
-    const task = {
-      scheduleTime: scheduleTime,
-      pull_message: {
-        payload: Buffer.from('a message for the recipient').toString('base64')
-      }
-    };
-
-    const request = {
-      parent: `projects/${project}/locations/${location}/queues/${queue}`,
-      resource: {
-        task: task
-      },
-      auth: authClient
-    };
-
-    cloudtasks.projects.locations.queues.tasks.create(request, (err, response) => {
-      if (err) {
-        console.error('ERROR:', err);
-        return;
-      }
-
+  return google.auth.getClient({
+    scopes: ['https://www.googleapis.com/auth/cloud-platform']
+  })
+    .then(authClient => {
+      // Schedule the task for 2 minutes from now
+      const scheduleTime = new Date();
+      scheduleTime.setUTCMinutes(scheduleTime.getUTCMinutes() + 2);
+
+      const task = {
+        scheduleTime: scheduleTime,
+        pull_message: {
+          payload: Buffer.from('a message for the recipient').toString('base64')
+        }
+      };
+
+      const request = {
+        parent: `projects/${project}/locations/${location}/queues/${queue}`,
+        resource: {
+          task: task
+        },
+        auth: authClient
+      };
+
+      return cloudtasks.projects.locations.queues.tasks.create(request);
+    })
+    .then(response => {
       console.log(`Created task ${response.data.name}.`);
       console.log(JSON.stringify(response.data, null, 2));
-    });
-  });
-
-  function authorize (callback) {
-    google.auth.getApplicationDefault(function (err, authClient) {
-      if (err) {
-        console.error('authentication failed: ', err);
-        return;
-      }
-      if (authClient.createScopedRequired && authClient.createScopedRequired()) {
-        var scopes = ['https://www.googleapis.com/auth/cloud-platform'];
-        authClient = authClient.createScoped(scopes);
-      }
-      callback(authClient);
-    });
-  }
+    })
+    .catch(console.error);
   // [END cloud_tasks_create_task]
 }
 
 function pullTask (project, location, queue) {
   // [START cloud_tasks_pull_and_acknowledge_task]
-  const google = require('googleapis').google;
+  const {google} = require('googleapis');
   const cloudtasks = google.cloudtasks('v2beta2');
 
   /**
@@ -86,42 +72,28 @@ function pullTask (project, location, queue) {
   // const location = 'Location of queue, e.g. us-central1';
   // const queue = 'Queue ID, e.g. queue-1';
 
-  authorize((authClient) => {
-    const request = {
-      parent: `projects/${project}/locations/${location}/queues/${queue}`,
-      responseView: 'FULL',
-      pageSize: 1,
-      auth: authClient
-    };
-
-    cloudtasks.projects.locations.queues.tasks.list(request, (err, response) => {
-      if (err) {
-        console.error(err);
-        return;
-      }
-
+  return google.auth.getClient({
+    scopes: ['https://www.googleapis.com/auth/cloud-platform']
+  })
+    .then(authClient => {
+      const request = {
+        parent: `projects/${project}/locations/${location}/queues/${queue}`,
+        responseView: 'FULL',
+        pageSize: 1,
+        auth: authClient
+      };
+
+      return cloudtasks.projects.locations.queues.tasks.list(request);
+    })
+    .then(response => {
       const task = response.data.tasks[0];
       console.log('Pulled task %j', task);
-    });
-  });
-
-  function authorize (callback) {
-    google.auth.getApplicationDefault(function (err, authClient) {
-      if (err) {
-        console.error('authentication failed: ', err);
-        return;
-      }
-      if (authClient.createScopedRequired && authClient.createScopedRequired()) {
-        var scopes = ['https://www.googleapis.com/auth/cloud-platform'];
-        authClient = authClient.createScoped(scopes);
-      }
-      callback(authClient);
-    });
-  }
+    })
+    .catch(console.error);
 }
 
 function acknowledgeTask (task) {
-  const google = require('googleapis').google;
+  const {google} = require('googleapis');
   const cloudtasks = google.cloudtasks('v2beta2');
 
   /**
@@ -132,36 +104,22 @@ function acknowledgeTask (task) {
   //   scheduleTime: '2017-11-01T21:02:28.994Z' // TODO(developer): set this to your task's scheduled time
   // };
 
-  authorize((authClient) => {
-    const request = {
-      name: task.name,
-      scheduleTime: task.scheduleTime,
-      auth: authClient
-    };
-
-    cloudtasks.projects.locations.queues.tasks.acknowledge(request, (err, response) => {
-      if (err) {
-        console.error(err);
-        return;
-      }
-
+  return google.auth.getClient({
+    scopes: ['https://www.googleapis.com/auth/cloud-platform']
+  })
+    .then(authClient => {
+      const request = {
+        name: task.name,
+        scheduleTime: task.scheduleTime,
+        auth: authClient
+      };
+
+      return cloudtasks.projects.locations.queues.tasks.acknowledge(request);
+    })
+    .then(response => {
       console.log(`Acknowledged task ${task.name}.`);
-    });
-  });
-
-  function authorize (callback) {
-    google.auth.getApplicationDefault(function (err, authClient) {
-      if (err) {
-        console.error('authentication failed: ', err);
-        return;
-      }
-      if (authClient.createScopedRequired && authClient.createScopedRequired()) {
-        var scopes = ['https://www.googleapis.com/auth/cloud-platform'];
-        authClient = authClient.createScoped(scopes);
-      }
-      callback(authClient);
-    });
-  }
+    })
+    .catch(console.error);
   // [END cloud_tasks_pull_and_acknowledge_task]
 }
 
diff --git a/kms/keys.js b/kms/keys.js
index 902aa5dce5..a7748a8150 100644
--- a/kms/keys.js
+++ b/kms/keys.js
@@ -1249,7 +1249,7 @@ function disableCryptoKeyVersion (projectId, locationId, keyRingId, cryptoKeyId,
 
   function buildAndAuthorizeService (callback) {
     // Imports the Google APIs client library
-    const google = require('googleapis').google;
+    const {google} = require('googleapis');
 
     // Acquires credentials
     google.auth.getApplicationDefault((err, authClient) => {
diff --git a/kms/quickstart.js b/kms/quickstart.js
index b385713bd5..ff95add002 100644
--- a/kms/quickstart.js
+++ b/kms/quickstart.js
@@ -17,7 +17,7 @@
 
 // [START kms_quickstart]
 // Imports the Google APIs client library
-const google = require('googleapis').google;
+const {google} = require('googleapis');
 
 // Your Google Cloud Platform project ID
 const projectId = process.env.GCLOUD_PROJECT;