Setup for Developing with the Cast Application Framework (CAF) for Web

The Google Cast Web Sender SDK lets you extend your Web app to control media, including video, movies, music, and games, on a TV or sound system.

The Web Sender Framework API provides a wrapper for the lower-level Base API. This framework simplifies and streamlines writing sender apps. The framework provides a simpler way to manage the Cast session and state, a Cast button implementation, and data binding to simplify implementation of a Cast remote player.

This guide describes how to register your Web Sender app and provides other information useful setup.


The Web Sender SDK is supported on Cast-supported web browsers on Mac, Windows, Linux, ChromeOS, and Android devices. For native mobile Cast apps see Android Apps and iOS Apps instead.

Updates to the Web Sender SDK occur automatically for all users, and provide fixes, user-facing features, and SDK capabilities. Updates are backwards-compatible and should be transparent to your site.


Other than registering your Web Receiver app and device, no special setup steps are required to use the Web Sender SDK.

To register your Web Receiver app and device follow the steps at Registration. Once you have your application ID, you're ready to develop your Web Sender app.

Add Web Sender API library to your project

To use the Web Sender API, include the following script in your web page:

<script src="//"></script>

Testing Cast buttons

While your Web Sender app should have its own Cast button, a user can also invoke the cast feature by choosing Cast from the right-click menu, as shown here:

The Chrome menu showing the Cast item highlighted

Your Web Sender app should handle both cases.

Chrome beta channel

A public beta channel for Chrome is also available. New versions of Chrome are pushed to the beta channel prior to a full release; the beta channel is also updated more often than the stable channel. This gives developers (and passionate early adopters) advance access to new features, and allows you to ensure that your site works with upcoming versions of Chrome.

To use the public beta channel:

  • Install the beta version of Chrome
  • To report issues, right-click on the Cast toolbar icon and choose "Report an issue". We can’t respond individually to most feedback, but we greatly value the input on the beta channel.
  • Before pushing updates to your live site, ensure that you test with the current stable version of Chrome. Most visitors to your site will have the stable version of Chrome installed, and if you depend on beta-only features, users with the stable version will be impacted.