Thanks for tackling this important feature!

On Tuesday, May 26, 2026 at 4:17:50 PM UTC+2 Noam Rosenthal wrote:

Contact emails 
[email protected], [email protected], [email protected] 

Explainer 
https://github.com/WICG/declarative-partial-updates/
blob/main/patching-explainer.md 

Specification 
https://github.com/whatwg/html/pull/11818


What's preventing the PR from landing?
 



Summary 
Use <template for> and processing instruction ranges (<?start> and 
<?end>, or <?marker) to update existing parts of the document without 
JS. 

Blink component 
Blink>HTML 

Web Feature ID 
No information provided 

Motivation 
Out of order streaming and partial updates are primitives that have 
been part of userland libraries for about a decade. 

Initial public proposal 
https://github.com/WICG/declarative-partial-updates 

TAG review 
https://github.com/w3ctag/design-reviews/issues/1134 

TAG review status 
Issues addressed 

Goals for experimentation 
None 

Risks 


Interoperability and Compatibility 
The main compat risk is re-introducing processing instructions, that 
were parsed as comments up until now. This is mitigated by disallowing 
HTML parsing of known processing instructions like <?xml-stylesheet?>, 
and avoiding special characters like $. It was heavily tested against 
the HTTP archive and ran in 50% Finch in beta. If new compat issues 
arise we can special-case particular processing instruction targets 
but it's likely not going to be necessary. 

Gecko: Proposed support 
(https://github.com/mozilla/standards-positions/issues/1369) 

WebKit: Support (https://github.com/WebKit/standards-positions/issues/628) 

Web developers: Positive 
(https://github.com/wicG/declarative-partial-updates) See issues in 
the WICG repo, lots of involvement from framework/CMS developers. 
There were some mixed reviews on some threads (e.g. 
https://news.ycombinator.com/item?id=48252957#48262499) 

Other signals: 

Enthusiasm (see the WICG repo) from frameworks and CMS like WordPress. 
Drupal already has an open issue to support this 
(https://www.drupal.org/project/drupal/issues/3590980) 

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 


Debuggability 
No information provided 

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

Is this feature fully tested by web-platform-tests? 
Yes 
https://wpt.fyi/results/html/dom/partial-updates/tentative?
label=experimental&aligned 

Flag name on about://flags 
None 

Finch feature name 
DocumentPatching 

Rollout plan 
Will ship enabled for all users 

Requires code in //chrome? 
False 

Tracking bug 
https://issues.chromium.org/issues/431374376 

Estimated milestones 
Shipping on desktop150 
DevTrial on desktop148 
Shipping on Android150 
DevTrial on Android148 
Shipping on WebView150 


Anticipated spec changes 

Open questions about a feature may be a source of future web compat or 
interop issues. Please list open issues (e.g. links to known github 
issues in the project for the feature specification) whose resolution 
may introduce web compat/interop risk (e.g., changing to naming or 
structure of the API in a non-backward-compatible way). 

There are a couple of small issues on the spec PR (e.g. how processing 
instruction attributes are parsed) but they are converging and the 
difference shouldn't be consequential. 

Link to entry on the Chrome Platform Status 
https://chromestatus.com/feature/5111042975465472?gate=5152413073539072 

Links to previous Intent discussions 
Intent to Prototype: 
https://groups.google.com/a/chromium.org/d/msgid/blink-
dev/6870fd9f.2b0a0220.2125de.0151.GAE%40google.com 


This intent message was generated by Chrome Platform Status. 

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