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Getting started with Chrome's origin trials

Origin trials are a way to test a new or experimental web platform feature, and give feedback to the web standards community on the feature's usability, practicality, and effectiveness, before the feature is made available to all users.

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Origin trials give you access to a new or experimental feature, to build functionality your users can try out for a limited time before the feature is made available to everyone.

When Chrome offers an origin trial for a feature, you can register for the trial to enable the feature for all users on your origin, without requiring them to toggle any flags or switch to an alternative build of Chrome (though they may need to upgrade). Origin trials enable developers to build demos and prototypes using new features. The trials also help Chrome engineers understand how new features are used, and how they may interact with other web technologies.

Origin trials are public and open to all developers. They are limited in duration and usage. Participation is a self-managed process with limited documentation and support. Participants should be willing and able to work relatively independently using the documentation available, which, at this stage, will likely be limited to API specifications and explainers, though web.dev tries to provide guidance whenever possible.

If you register for a trial, the Chrome team will periodically ask you for specific feedback on your use of the trial feature. Some features may undergo multiple origin trials, as learnings are incorporated and adjustments are made.

Third-party origin trials

Origin trials are usually only available on a first-party basis: they only work for a single registered origin. Third-party origin trials make it possible for providers of embedded content to try a new feature across multiple sites without requiring a token for every origin.

Find out more: What are third-party origin trials?

Deprecation trials

Not all origin trials are for testing new APIs. Some trials enable a deprecated feature to be temporarily re-enabled. These are known as deprecation trials, and in some contexts have been referred to as "reverse" origin trials.

For example, from Chrome 85 AppCache is no longer available in Chrome by default. Sites needing extra time to migrate off AppCache could register for the deprecation trial to continue using AppCache until Chrome 93.

How to register for an origin trial

  1. Choose an origin trial from the list of active trials.
  2. Request a token by clicking the Register button and filling out the form.
  3. Add the token to your web pages, using one of the following methods:
    • As a meta tag in the <head> of each page served: <meta http-equiv="origin-trial" content="TOKEN_GOES_HERE">
    • As an HTTP header: Origin-Trial: TOKEN_GOES_HERE
  4. Try out the new feature.
  5. Submit feedback. Do this through the origin trial site. This feedback is not public and is available only to a limited group of people on the Chrome team. Each trial also provides a link for spontaneous community feedback. This typically points to the feature on GitHub or some other public channel.
  6. When your token expires, you will get an email with a renewal link. To do so, you are again asked to submit feedback.

Usually if an API lands unchanged after a successful origin trial, there is a short period between the end of the origin trial and the date the implementation ships in the browser when the API will not be available. This is by design. If Chrome were to avoid the mandatory total-breakage period, that would bias toward also avoiding breakages in the API surface, which are often needed to improve the API. The final shipping API might be worse for it.

In rare circumstances, if there was clear evidence that developers engaged with the origin trial and that their concerns were taken into account in the final API design and implementation, this breakage period may be skipped upon request.

View origin trials information in DevTools

Available from Chrome 94. You can now get information about a site's origin trials in DevTools under the Application panel.

Origin trials in the Frame details view

Find out more

Photo by Louis Reed on Unsplash.

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