Welcome to the Google Home Developer Center, the new destination for learning how to develop smart home actions.

Test and debug your app

We recommend that you build your local fulfillment app using the steps described earlier, then test your smart home integration on your own hosting environment using the following steps:

In your own hosting environment, serve the HTML page that runs your local fulfillment app. The following snippet shows an example of a static HTML file that runs your local fulfillment app.

<html>
  <head>
    <!-- Local Home SDK -->
    <script src="//www.gstatic.com/eureka/smarthome/smarthome_sdk.js"></script>
    <!-- Local app under development -->
    <script src="local_execution.js"></script>
  </head>

</html>

Test device control.
Debug from Chrome. Use breakpoints and logs to troubleshoot your integration.
Modify and compile your TypeScript code, then repeat these steps.

By repeating this build-and-test process, you can see your changes in action quickly to help you debug issues with your code.

Test device control

In the Google Home Developer Console, you need to specify the URL of your web app, which serves the HTML that gets loaded on the Google Home or Google Nest device during local fulfillment.

To test device control with local fulfillment, follow these steps:

Chrome

In the Setup and configuration page of your Cloud-to-cloud integration in the Google Home Developer Console, scroll to Local fulfillment and toggle the setting on.
Under Testing URLs > Testing URL for Chrome, specify the development server URL that serves the HTML that runs your local fulfillment app.
Click Save. It may take up to 30 minutes for Google to propagate your console changes.
Reboot your test Google Home or Google Nest device.
Issue a command to your smart device. For example, if your device implements the OnOff trait, you could say "Hey Google, turn on the lights."

Node.js

In the Setup and configuration page of the Google Home Developer Console, scroll to Local fulfillment and toggle the setting on.
Under Testing URLs > Testing URL for Node, specify the development server URL that serves the JavaScript that runs your local fulfillment app.
Click Save. It may take up to 30 minutes for Google to propagate your console changes.
Reboot your test Google Home or Google Nest device.
Issue a command to your smart device. For example, if your device implements the OnOff trait, you could say "Hey Google, turn on the lights."

For more details on which runtime is used by your device, see Supported devices.

Debug from Chrome

You can debug your local fulfillment app using Chrome DevTools. Before you can debug, make sure that your environment is correctly set up:

You have set your development URL in the console to a URL reachable by the Google Home or Google Nest device (either on the local area network or using the internet),
Your machine is connected to the same local area network as the Google Home or Google Nest device you are testing.
Your network doesn't block packets between devices.
You are logged in with the same Google Account on the Google Home Developer Console and on the Google Home or Google Nest device.
You have updated the SYNC response in your cloud fulfillment. It should return at least one valid value in the otherDeviceIds field.
You have entered the correct scan config information in the Google Home Developer Console.

To connect your local fulfillment app to the Chrome DevTools debugger, follow these steps:

Chrome

In your local development machine, install and launch the Google Chrome browser.
In the address field of your Chrome browser, launch the Chrome inspector by entering: chrome://inspect#devices. You should see a list of devices on the page, and your HTML file should be listed under the name of your test Google Home or Google Nest device.
Click the blue inspect link under your HTML to launch Chrome DevTools. Switch to the Console tab. The Local Home platform outputs your app version and the Local Home SDK version in the console log. If you see the log, it means that Google has loaded your app successfully, and is able to connect to it. If not, reboot your Google Home or Google Nest device.

Node.js

In your local development machine, install and launch the Google Chrome browser.
Determine the local IP address of your test device.
In the address field of your Chrome browser, launch the Chrome inspector by entering: chrome://inspect#devices.
Select Configure... to open the Target discovery settings.

Figure 2: Target discovery settings in chrome://inspect.

Enter DEVICE_IP_ADDRESS:9222 in the list and click Done.
Click the blue inspect link under your script to launch Chrome DevTools. Switch to the Console tab. The Local Home platform outputs your app version and the Local Home SDK version in the console log. If you see the log, it means that Google has loaded your app successfully, and is able to connect to it. If not, reboot your Google Home or Google Nest device.

For more details on which runtime is used by your device, see Supported Devices.

Debugging tips

Some additional things to keep in mind during debugging include:

Don't link multiple Google Home or Google Nest devices to your test account on the same local network. You won't be able to control which Google Home or Google Nest device is targeted with the local fulfillment commands.
Refresh the page in Chrome DevTools to reload your local fulfillment app container with the latest code from your development URL. This does not reset the Local Home platform, which may be necessary to re-trigger platform intents (such as IDENTIFY) in your local fulfillment app. To reset the Local Home platform, reboot your Google Home or Google Nest device.
Check that your JavaScript app loads without errors. To do this, check the console section of the DevTools page. If there is a problem, you will see a message like this: 'Uncaught TypeError: Cannot read property 'open' of null.'
The verificationId from the IDENTIFY response must match one of the otherDeviceIds from the SYNC response.
For the EXECUTE handler, make sure your HTTP, TCP, or UDP commands can be received by your device and work as expected.
Make sure to return a Promise from the handlers.
Avoid maintaining global state in memory. See Application lifecycle.
Errors thrown by your local fulfillment app will appear in your project error logs.

Prepare and launch to production

When you are ready to launch your smart home Action, follow these steps:

Open a terminal. In your project directory, run the npm run build command. This command generates the following JavaScript bundles for your app under the dist directory:
```
project-directory/
└── dist
 ├── web
 │    └── bundle.js
 └── node
      └── bundle.js
```
In the Setup and configuration page of the Google Home Developer Console, scroll to Local fulfillment and toggle the setting on.
Using the Upload JavaScript buttons, upload the bundle files that you previously generated.

Figure 3: Upload your JavaScript app.
Make sure to upload both versions of the bundle files (Node, Web) so that your Action is configured to work correctly across all runtime environments that local fulfillment supports.
1. Upload your JavaScript targeting Node.js: Upload the bundle.js file from the dist/node directory.
2. Upload your JavaScript targeting Chrome (browser): Upload the bundle.js file from the dist/web directory.
Test your Action on an Assistant-enabled device, to verify that it behaves as expected in a production environment. To learn more, see Test and share your smart home Action.
When you are satisfied with how your Action works, submit it to Google for production deployment by following the instructions in Launch your smart home Action. This includes completing the self-test and certification request steps.

Implement local fulfillment app