Intent to Extend Experiment: SharedWorker on Android

[Yoshisato Yanagisawa]

Contact emails

yyana...@google.com, dom...@chromium.org

Specification

https://html.spec.whatwg.org/multipage/workers.html#shared-workers-and-the-sharedworker-interface

Summary

For a long time, SharedWorker has been disabled on Android due to concerns about its unpredictable process lifecycle. We believed that SharedWorker instances might terminate unexpectedly, without noticing to users or web developers, which we considered unacceptable. However, a recent discussion on GitHub (https://github.com/whatwg/html/issues/11205) suggests that the unpredictable nature of SharedWorker's process lifecycle might not be as significant an issue as we once thought. Based on this, we plan to re-enable SharedWorker on Android while simultaneously investigating this behavior to ensure a stable and reliable experience.

Blink component

Blink>Workers

Web Feature ID

shared-workers

TAG review

No information provided

TAG review status

Not applicable

Origin Trial Name

SharedWorker on Android

Chromium Trial Name

SharedWorkerOnAndroid

Origin Trial documentation link

https://developer.mozilla.org/en-US/docs/Web/API/SharedWorker

WebFeature UseCounter name

kSharedWorkerStartOnAndroid

Risks

Interoperability and Compatibility

While Chrome has been the sole major browser not to offer SharedWorker, this change aims to close that gap. However, unlike on desktop, Android's unpredictable process lifecycle presents a unique risk. SharedWorker instances might terminate unexpectedly, for example, when a Chrome app is moved to the background and then foregrounded. This inherent uncertainty in the Android environment is a key risk when running SharedWorker.

Gecko: Shipped/Shipping

WebKit: Shipped/Shipping

Web developers: Positive As you can see in http://crbug.com/40290702, SharedWorker support on Android has been a long-awaited feature by web developers. This demonstrates a clear and sustained demand from the developer community for this capability.

Other signals:

Ergonomics

n/a

Activation

n/a

Security

This feature is already shipped on desktop, and no new security risks are introduced with the Android implementation.

WebView application risks

Does this intent deprecate or change behavior of existing APIs, such that it has potentially high risk for Android WebView-based applications?

No information provided

Goals for experimentation

No information provided

Reason this experiment is being extended

A major partner is about to start a large-scale experiment. We believe that extending the trial to cover their experiment window is crucial, as it will provide us with essential performance metrics and stability data at scale. This extension will prevent any service disruption for the partner and ensure we have sufficient evidence to support the final launch.

Ongoing technical constraints

None.

Debuggability

This feature is already shipped on desktop, and no new debuggability issues should be introduced with the Android implementation.

Will this feature be supported on all six Blink platforms (Windows, Mac, Linux, ChromeOS, Android, and Android WebView)?

No
This aims to make SharedWorker supported on Android and Android WebView. SharedWorker has been supported other than them.

Is this feature fully tested by web-platform-tests?

Yes
SharedWorker tests under https://wpt.fyi/results/workers. e.g. https://wpt.fyi/results/workers/SharedWorker-simple.html Note that since wpt.fyi runs tests on Linux not Android for Chromium.

DevTrial instructions

https://developer.mozilla.org/en-US/docs/Web/API/SharedWorker/SharedWorker

Flag name on about://flags

No information provided

Finch feature name

SharedWorker

Requires code in //chrome?

False

Tracking bug

https://crbug.com/40290702

Measurement

SharedWorkerStart filtered by Android.

Estimated milestones

Origin trial desktop first	140
Origin trial desktop last	144
Origin trial extension 1 end milestone	147
Origin trial Android first	140
Origin trial Android last	144
DevTrial on Android	140

Link to entry on the Chrome Platform Status

https://chromestatus.com/feature/6265472244514816?gate=4824380645441536

Links to previous Intent discussions

Intent to Experiment: https://groups.google.com/a/chromium.org/d/msgid/blink-dev/6879be98.2b0a0220.72055.015d.GAE%40google.com

This intent message was generated by Chrome Platform Status.

[Mike Taylor]

Typically we ask folks to answer a few questions about progress before approving OT extensions. But this experiment is different enough that they don't make a lot of sense IMHO. That said, is there anything you can share from what you have learned from the first 4 milestones the experiment has been available?

--
You received this message because you are subscribed to the Google Groups "blink-dev" group.
To unsubscribe from this group and stop receiving emails from it, send an email to blink-dev+...@chromium.org.
To view this discussion visit https://groups.google.com/a/chromium.org/d/msgid/blink-dev/CAPNB-6VPRn%2BLp%2B61oJOc2e3fnY3F1LaZ2f2g_LTsA%3DXv49FzgQ%40mail.gmail.com.

[Yoshisato Yanagisawa]

Thank you for the question. Here is what we've learned from the first four milestones:

Looking at the UMA data, we have observed instances of the feared "Worker connection lost" events, confirming the process lifecycle concerns are valid, albeit the occurrences are extremely rare. Based on this limited sample, it does not appear to be the majority reason for SharedWorker termination. However, we do not yet have the statistical volume of data to draw firm conclusions or have a more in-depth discussion on the statistics.

On the positive side, we’ve had over 10 Origin Trial sign-ups since October, and we've seen a few more this month, potentially due to the efforts referenced in the GitHub issue (https://github.com/web-platform-tests/interop/issues/1064). We will continue to closely monitor the results.

Best regards,
Yoshisato

2026年1月8日(木) 23:41 Mike Taylor <mike...@chromium.org>: