diff --git a/translate/package.json b/translate/package.json
index b7b1f938050..ef36037b91b 100644
--- a/translate/package.json
+++ b/translate/package.json
@@ -5,16 +5,12 @@
   "license": "Apache Version 2.0",
   "author": "Google Inc.",
   "scripts": {
-    "test": "mocha -R spec --require intelli-espower-loader ../test/_setup.js test/*.test.js",
-    "system-test": "mocha -R spec --require intelli-espower-loader ../system-test/_setup.js system-test/*.test.js"
+    "test": "cd ..; npm run st -- translate/system-test/*.test.js"
   },
   "dependencies": {
-    "@google-cloud/translate": "^0.4.0",
+    "@google-cloud/translate": "^0.5.0",
     "yargs": "^6.4.0"
   },
-  "devDependencies": {
-    "mocha": "^3.1.2"
-  },
   "engines": {
     "node": ">=4.3.2"
   }
diff --git a/translate/quickstart.js b/translate/quickstart.js
index 2ed38c9ba57..7bb0715b24b 100644
--- a/translate/quickstart.js
+++ b/translate/quickstart.js
@@ -19,12 +19,12 @@
 // Imports the Google Cloud client library
 const Translate = require('@google-cloud/translate');
 
-// Your Translate API key
-const apiKey = 'YOUR_API_KEY';
+// Your Google Cloud Platform project ID
+const projectId = 'YOUR_PROJECT_ID';
 
 // Instantiates a client
 const translateClient = Translate({
-  key: apiKey
+  projectId: projectId
 });
 
 // The text to translate
@@ -33,13 +33,11 @@ const text = 'Hello, world!';
 const target = 'ru';
 
 // Translates some text into Russian
-translateClient.translate(text, target, (err, translation) => {
-  if (err) {
-    console.error(err);
-    return;
-  }
+translateClient.translate(text, target)
+  .then((results) => {
+    const translation = results[0];
 
-  console.log(`Text: ${text}`);
-  console.log(`Translation: ${translation}`);
-});
+    console.log(`Text: ${text}`);
+    console.log(`Translation: ${translation}`);
+  });
 // [END translate_quickstart]
diff --git a/translate/system-test/quickstart.test.js b/translate/system-test/quickstart.test.js
index 640b1afeb78..d41753da339 100644
--- a/translate/system-test/quickstart.test.js
+++ b/translate/system-test/quickstart.test.js
@@ -16,39 +16,37 @@
 'use strict';
 
 const proxyquire = require(`proxyquire`).noPreserveCache();
-const translate = proxyquire(`@google-cloud/translate`, {})({
-  key: process.env.TRANSLATE_API_KEY
-});
-const string = `Hello, world!`;
-const expectedTranslation = `Привет мир!`;
-const targetLanguage = `ru`;
+const translate = proxyquire(`@google-cloud/translate`, {})();
 
 describe(`translate:quickstart`, () => {
-  let translateMock, TranslateMock;
-
   it(`should translate a string`, (done) => {
-    translateMock = {
-      translate: (_string, _targetLanguage, _callback) => {
+    const string = `Hello, world!`;
+    const expectedTranslation = `Привет мир!`;
+    const targetLanguage = `ru`;
+    const translateMock = {
+      translate: (_string, _targetLanguage) => {
         assert.equal(_string, string);
         assert.equal(_targetLanguage, targetLanguage);
-        assert.equal(typeof _callback, 'function');
 
-        translate.translate(_string, _targetLanguage, (err, translation, apiResponse) => {
-          _callback(err, translation, apiResponse);
-          assert.ifError(err);
-          assert.equal(translation, expectedTranslation);
-          assert.notEqual(apiResponse, undefined);
-          assert.equal(console.log.calledTwice, true);
-          assert.deepEqual(console.log.firstCall.args, [`Text: ${string}`]);
-          assert.deepEqual(console.log.secondCall.args, [`Translation: ${expectedTranslation}`]);
-          done();
-        });
+        return translate.translate(_string, _targetLanguage)
+          .then((results) => {
+            const translation = results[0];
+            assert.equal(translation, expectedTranslation);
+
+            setTimeout(() => {
+              assert.equal(console.log.callCount, 2);
+              assert.deepEqual(console.log.getCall(0).args, [`Text: ${string}`]);
+              assert.deepEqual(console.log.getCall(1).args, [`Translation: ${expectedTranslation}`]);
+              done();
+            }, 200);
+
+            return results;
+          });
       }
     };
-    TranslateMock = sinon.stub().returns(translateMock);
 
     proxyquire(`../quickstart`, {
-      '@google-cloud/translate': TranslateMock
+      '@google-cloud/translate': sinon.stub().returns(translateMock)
     });
   });
 });
diff --git a/translate/system-test/translate.test.js b/translate/system-test/translate.test.js
index acfb60678d9..8d49dd92f38 100644
--- a/translate/system-test/translate.test.js
+++ b/translate/system-test/translate.test.js
@@ -22,45 +22,57 @@ const run = require(`../../utils`).run;
 const cwd = path.join(__dirname, `..`);
 const cmd = `node translate.js`;
 const text = `Hello world!`;
+const text2 = `Goodbye!`;
 const toLang = `ru`;
 
 describe(`translate:translate`, () => {
-  const translate = Translate({
-    key: process.env.TRANSLATE_API_KEY
-  });
-  if (!process.env.TRANSLATE_API_KEY) {
-    process.stdout.write(`Skipping Translate API tests...\n`);
-    return;
-  }
+  const translate = Translate();
 
-  it(`should detect language`, (done) => {
+  it(`should detect language of a single string`, () => {
     const output = run(`${cmd} detect "${text}"`, cwd);
-    translate.detect(text, (err, result) => {
-      assert.ifError(err);
-      assert.equal(output, `Detected: ${JSON.stringify(result)}`);
-      done();
-    });
+    return translate.detect(text)
+      .then((results) => {
+        const expected = `Detections:\n${text} => ${results[0].language}`;
+        assert.equal(output, expected);
+      });
+  });
+
+  it(`should detect language of multiple strings`, () => {
+    const output = run(`${cmd} detect "${text}" "${text2}"`, cwd);
+    return translate.detect([text, text2])
+      .then((results) => {
+        const expected = `Detections:\n${text} => ${results[0][0].language}\n${text2} => ${results[0][1].language}`;
+        assert.equal(output, expected);
+      });
   });
 
   it(`should list languages`, () => {
     const output = run(`${cmd} list`, cwd);
-    assert.notEqual(output.indexOf(`Languages:`), -1);
-    assert.notEqual(output.indexOf(`{ code: 'af', name: 'Afrikaans' }`), -1);
+    assert.equal(output.includes(`Languages:`), true);
+    assert.equal(output.includes(`{ code: 'af', name: 'Afrikaans' }`), true);
   });
 
   it(`should list languages with a target`, () => {
     const output = run(`${cmd} list es`, cwd);
-    assert.notEqual(output.indexOf(`Languages:`), -1);
-    assert.notEqual(output.indexOf(`{ code: 'af', name: 'afrikáans' }`), -1);
+    assert.equal(output.includes(`Languages:`), true);
+    assert.equal(output.includes(`{ code: 'af', name: 'afrikáans' }`), true);
   });
 
-  it(`should translate text`, (done) => {
+  it(`should translate a single string`, () => {
     const output = run(`${cmd} translate ${toLang} "${text}"`, cwd);
-    translate.translate(text, toLang, (err, translation) => {
-      assert.ifError(err);
-      assert.notEqual(output.indexOf(`Text: ["${text}"]`), -1);
-      assert.notEqual(output.indexOf(`Translation: "${translation}"`), -1);
-      done();
-    });
+    return translate.translate(text, toLang)
+      .then((results) => {
+        const expected = `Translations:\n${text} => (${toLang}) ${results[0]}`;
+        assert.equal(output, expected);
+      });
+  });
+
+  it(`should translate multiple strings`, () => {
+    const output = run(`${cmd} translate ${toLang} "${text}" "${text2}"`, cwd);
+    return translate.translate([text, text2], toLang)
+      .then((results) => {
+        const expected = `Translations:\n${text} => (${toLang}) ${results[0][0]}\n${text2} => (${toLang}) ${results[0][1]}`;
+        assert.equal(output, expected);
+      });
   });
 });
diff --git a/translate/test/quickstart.test.js b/translate/test/quickstart.test.js
deleted file mode 100644
index e9c3dd683d2..00000000000
--- a/translate/test/quickstart.test.js
+++ /dev/null
@@ -1,43 +0,0 @@
-/**
- * Copyright 2016, Google, Inc.
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-'use strict';
-
-const proxyquire = require(`proxyquire`).noCallThru();
-
-describe(`translate:quickstart`, () => {
-  let translateMock, TranslateMock;
-  const error = new Error(`error`);
-
-  before(() => {
-    translateMock = {
-      translate: sinon.stub().yields(error)
-    };
-    TranslateMock = sinon.stub().returns(translateMock);
-  });
-
-  it(`should handle error`, () => {
-    proxyquire(`../quickstart`, {
-      '@google-cloud/translate': TranslateMock
-    });
-
-    assert.equal(TranslateMock.calledOnce, true);
-    assert.deepEqual(TranslateMock.firstCall.args, [{ key: 'YOUR_API_KEY' }]);
-    assert.equal(translateMock.translate.calledOnce, true);
-    assert.deepEqual(translateMock.translate.firstCall.args.slice(0, -1), ['Hello, world!', 'ru']);
-    assert.equal(console.error.calledOnce, true);
-    assert.deepEqual(console.error.firstCall.args, [error]);
-  });
-});
diff --git a/translate/test/translate.test.js b/translate/test/translate.test.js
deleted file mode 100644
index 91b296c3c05..00000000000
--- a/translate/test/translate.test.js
+++ /dev/null
@@ -1,44 +0,0 @@
-/**
- * Copyright 2016, Google, Inc.
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-'use strict';
-
-const proxyquire = require(`proxyquire`).noCallThru();
-
-describe(`translate:translate`, () => {
-  it(`should handle errors`, () => {
-    const error = new Error(`error`);
-    const text = `Hello world!`;
-    const toLang = `ru`;
-    const callback = sinon.spy();
-    const translateMock = {
-      getLanguages: sinon.stub().yields(error),
-      detect: sinon.stub().yields(error),
-      translate: sinon.stub().yields(error)
-    };
-    const TranslateMock = sinon.stub().returns(translateMock);
-    const program = proxyquire(`../translate`, {
-      '@google-cloud/translate': TranslateMock
-    });
-
-    program.detectLanguage(text, callback);
-    program.listLanguages(callback);
-    program.listLanguagesWithTarget(toLang, callback);
-    program.translateText(text, toLang, callback);
-
-    assert.equal(callback.callCount, 4);
-    assert.equal(callback.alwaysCalledWithExactly(error), true);
-  });
-});
diff --git a/translate/translate.js b/translate/translate.js
index bc3e1087024..1f7b3166544 100644
--- a/translate/translate.js
+++ b/translate/translate.js
@@ -18,156 +18,130 @@
 const Translate = require('@google-cloud/translate');
 
 // [START translate_detect_language]
-function detectLanguage (input, callback) {
+function detectLanguage (input) {
   // Instantiates a client
-  const translate = Translate({
-    // The Translate API uses an API key for authentication. This sample looks
-    // for the key in an environment variable.
-    key: process.env.TRANSLATE_API_KEY
-  });
+  const translate = Translate();
 
   // Detects the language. "input" can be a string for detecting the language of
   // a single piece of text, or an array of strings for detecting the languages
   // of multiple texts.
-  translate.detect(input, (err, result) => {
-    if (err) {
-      callback(err);
-      return;
-    }
+  return translate.detect(input)
+    .then((results) => {
+      let detections = results[0];
+
+      if (!Array.isArray(detections)) {
+        detections = [detections];
+      }
+
+      console.log('Detections:');
+      detections.forEach((detection) => {
+        console.log(`${detection.input} => ${detection.language}`);
+      });
 
-    console.log('Detected: %j', result);
-    callback();
-  });
+      return detections;
+    });
 }
 // [END translate_detect_language]
 
 // [START translate_list_codes]
-function listLanguages (callback) {
+function listLanguages () {
   // Instantiates a client
-  const translate = Translate({
-    // The Translate API uses an API key for authentication. This sample looks
-    // for the key in an environment variable.
-    key: process.env.TRANSLATE_API_KEY
-  });
+  const translate = Translate();
 
   // Lists available translation language with their names in English (the default).
-  translate.getLanguages((err, languages) => {
-    if (err) {
-      callback(err);
-      return;
-    }
+  return translate.getLanguages()
+    .then((results) => {
+      const languages = results[0];
+
+      console.log('Languages:');
+      languages.forEach((language) => console.log(language));
 
-    console.log('Languages:');
-    languages.forEach((language) => console.log(language));
-    callback();
-  });
+      return languages;
+    });
 }
 // [END translate_list_codes]
 
 // [START translate_list_language_names]
-function listLanguagesWithTarget (target, callback) {
+function listLanguagesWithTarget (target) {
   // Instantiates a client
-  const translate = Translate({
-    // The Translate API uses an API key for authentication. This sample looks
-    // for the key in an environment variable.
-    key: process.env.TRANSLATE_API_KEY
-  });
-
-  // Lists available translation language with their names in a target language
-  translate.getLanguages(target, (err, languages) => {
-    if (err) {
-      callback(err);
-      return;
-    }
+  const translate = Translate();
+
+  // Lists available translation language with their names in a target language,
+  // e.g. "ru"
+  return translate.getLanguages(target)
+    .then((results) => {
+      const languages = results[0];
+
+      console.log('Languages:');
+      languages.forEach((language) => console.log(language));
 
-    console.log('Languages:');
-    languages.forEach((language) => console.log(language));
-    callback();
-  });
+      return languages;
+    });
 }
 // [END translate_list_language_names]
 
 // [START translate_translate_text]
-function translateText (input, target, callback) {
+function translateText (input, target) {
+  if (!Array.isArray(input)) {
+    input = [input];
+  }
+
   // Instantiates a client
-  const translate = Translate({
-    // The Translate API uses an API key for authentication. This sample looks
-    // for the key in an environment variable.
-    key: process.env.TRANSLATE_API_KEY
-  });
+  const translate = Translate();
 
   // Translates the text into the target language. "input" can be a string for
   // translating a single piece of text, or an array of strings for translating
   // multiple texts.
-  translate.translate(input, target, (err, translation) => {
-    if (err) {
-      callback(err);
-      return;
-    }
-
-    console.log('Text: %j', input);
-    console.log('Translation: %j', translation);
-    callback();
-  });
+  return translate.translate(input, target)
+    .then((results) => {
+      let translations = results[0];
+      translations = Array.isArray(translations) ? translations : [translations];
+
+      console.log('Translations:');
+      translations.forEach((translation, i) => {
+        console.log(`${input[i]} => (${target}) ${translation}`);
+      });
+
+      return translations;
+    });
 }
 // [END translate_translate_text]
 
-// The command-line program
-const cli = require(`yargs`);
-const noop = require(`../utils`).noop;
-
-const program = module.exports = {
-  detectLanguage: detectLanguage,
-  listLanguages: listLanguages,
-  listLanguagesWithTarget: listLanguagesWithTarget,
-  translateText: translateText,
-  main: (args) => {
-    // Run the command-line program
-    cli.help().strict().parse(args).argv;
-  }
-};
-
-cli
+require(`yargs`)
   .demand(1)
-  .command(`detect <input..>`, `Detects the language of the provided text or texts`, {}, (opts) => {
-    if (!process.env.TRANSLATE_API_KEY) {
-      process.env.TRANSLATE_API_KEY = opts.apiKey;
-    }
-    program.detectLanguage(opts.input, noop);
-  })
-  .command(`list [target]`, `Lists available translation languages. To return language names in a language other than English, specify a target language.`, {}, (opts) => {
-    if (!process.env.TRANSLATE_API_KEY) {
-      process.env.TRANSLATE_API_KEY = opts.apiKey;
+  .command(
+    `detect <input..>`,
+    `Detects the language of one or more strings.`,
+    {},
+    (opts) => detectLanguage(opts.input)
+  )
+  .command(
+    `list [target]`,
+    `Lists available translation languages. To return language names in a language other than English, specify a target language.`,
+    {},
+    (opts) => {
+      if (opts.target) {
+        listLanguagesWithTarget(opts.target);
+      } else {
+        listLanguages();
+      }
     }
-    if (opts.target) {
-      program.listLanguagesWithTarget(opts.target, noop);
-    } else {
-      program.listLanguages(noop);
-    }
-  })
-  .command(`translate <toLang> <input..>`, `Translates the provided text or texts to the target language.`, {}, (opts) => {
-    if (!process.env.TRANSLATE_API_KEY) {
-      process.env.TRANSLATE_API_KEY = opts.apiKey;
-    }
-    program.translateText(opts.input, opts.toLang, noop);
-  })
-  .option(`apiKey`, {
-    alias: `k`,
-    global: true,
-    requiresArg: true,
-    default: process.env.TRANSLATE_API_KEY,
-    type: `string`,
-    description: `Your Translate API key. Defaults to the value of the TRANSLATE_API_KEY environment variable.`
-  })
-  .example(`node $0 detect "Hello world!"`, `Detects the language of "Hello world!".`)
-  .example(`node $0 detect -k YOUR_API_KEY "Hello world!" "Goodbye"`, `Detects the language of "Hello world!" and "Goodbye", supplying the API key inline.`)
-  .example(`node $0 list -k YOUR_API_KEY`, `Lists available translation languages with names in English, supplying the API key inline.`)
+  )
+  .command(
+    `translate <toLang> <input..>`,
+    `Translates one or more strings into the target language.`,
+    {},
+    (opts) => translateText(opts.input, opts.toLang)
+  )
+  .example(`node $0 detect "Hello world!"`, `Detects the language of a string.`)
+  .example(`node $0 detect "Hello world!" "Goodbye"`, `Detects the languages of multiple strings.`)
+  .example(`node $0 list`, `Lists available translation languages with names in English.`)
   .example(`node $0 list es`, `Lists available translation languages with names in Spanish.`)
-  .example(`node $0 translate ru "Good morning!"`, `Translates "Good morning!" to Russian, auto-detecting the source language.`)
+  .example(`node $0 translate ru "Good morning!"`, `Translates a string into Russian.`)
+  .example(`node $0 translate ru "Good morning!" "Good night!"`, `Translates multiple strings into Russian.`)
   .wrap(120)
   .recommendCommands()
-  .epilogue(`For more information, see https://cloud.google.com/translate/docs`);
-
-if (module === require.main) {
-  program.main(process.argv.slice(2));
-}
+  .epilogue(`For more information, see https://cloud.google.com/translate/docs`)
+  .help()
+  .strict()
+  .argv;