Intent to Continue Experimenting: Handwriting Recognition API

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Jiewei Qian

Dec 21, 2021, 10:33:08 PM12/21/21
to blink-dev, Glen Robertson, Chris Harrelson

Contact emails



Design docs


An API for web applications to make use of advanced handwriting recognition services (e.g. those on operating systems) to recognize text from handwriting drawings (inks) in real time. In this context, handwriting drawing means the temporal and positional information used to describe a human handwriting process.

Blink component


TAG review

TAG review status

Issues addressed

Link to origin trial feedback summary


Interoperability and Compatibility

Different browsers (and operating systems) will expose different underlying implementations and produce different outputs given the same input. We think this is acceptable given the implementation is machine-learning based, and it is not feasible or desirable to precisely specify the expected output for a given input in a standard. In the past, we have taken this approach for the Web Speech and Shape Detection APIs.

Gecko: No signal ( Feedback requested, no reply yet.

WebKit: No signal ( Feedback requested, no reply yet.

Web developers: Positive ( Twitter:

Other signals:

Goals for experimentation

- General API design. Determine if the API design satisfies the App developer's use cases - Specifically, we want to see if the current API design provides sufficient information (in the result) to enable web developers to make use of this feature.

Reason this experiment is being extended

No gap before shipping.

Revised timeline: Original origin trial - first milestone: M91 Original origin trial - last milestone: M97 Extended origin trial - last milestone: M98

Ongoing technical constraints



N/A. Existing DevTools tooling works for this feature.

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


Initially we will implement this feature on Chrome OS, since it has handwriting recognition service ready for use. We will need to do additional work to integrate with other platforms. Handwriting recognition capabilities already exist on all other platforms. We will do other I2E / I2S for implementing this on other platforms, due to the different security and privacy implications.

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

No. Full coverage relies on platform-specific implementation. WPT only tests failure cases.

Flag name

Requires code in //chrome?


Tracking bug

Launch bug

Estimated milestones

OriginTrial desktop last98
OriginTrial desktop first

Intent to Ship


Link to entry on the Chrome Platform Status

Links to previous Intent discussions

Intent to prototype:
Intent to Experiment:

Chris Harrelson

Jan 3, 2022, 2:36:21 PMJan 3
to Jiewei Qian, blink-dev, Glen Robertson

Jiewei Qian

Jan 6, 2022, 11:39:59 PMJan 6
to Chris Harrelson, blink-dev, Glen Robertson
Hi Blink Owners,

We are shipping the API in M99, but want to avoid a gap for users yet to update from M98. 

We are asking to extend the OT end date (currently 2022-02-22, one week before M99 release) to 2022-04-15 (two weeks after M100 release), without changing the end milestone.

This should allow enough time for users to update.

The API shipped in M99 is the same as the one under origin trial.

Thanks for considering.

Daniel Bratell

Jan 7, 2022, 2:41:54 AMJan 7
to Jiewei Qian, Chris Harrelson, blink-dev, Glen Robertson

One of the reasons that the process dictates a gap is to remove the pressure to ship an imperfect API. For us to consider a gap-less shipping we therefore want to be sure that feedback has been taken into account and incorporated into the API. Can you point to such examples?


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Glen Robertson

Jan 9, 2022, 7:36:00 PMJan 9
to Daniel Bratell, Jiewei Qian, Chris Harrelson, blink-dev
As discussed in an earlier thread ( we have only received OT feedback from 1 developer, but it has been positive. There is also some feedback as issues on github ( It has all either been addressed or does not require changes to the API.

Jiewei Qian

Jan 18, 2022, 11:33:54 PMJan 18
to Glen Robertson, Daniel Bratell, Chris Harrelson, blink-dev
Friendly ping :)

Chris Harrelson

Jan 19, 2022, 11:03:59 AMJan 19
to Jiewei Qian, Glen Robertson, Daniel Bratell, blink-dev
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