Contact emails
[email protected]

Explainer
https://github.com/w3c/webtransport/blob/main/explainer.md#5-sending-and-receiving-datagrams


Specification
https://www.w3.org/TR/webtransport/#datagram-writable


Summary
Adds the modern WebTransport Datagram sending API. 
WebTransportDatagramDuplexStream.createWritable() creates independent 
WebTransportDatagramsWritable streams. Each writable has mutable sendGroup and 
sendOrder attributes for expressing relative priority among queued WebTransport 
data in the same send group. Chromium currently applies this ordering among 
Datagram writables. The implementation also reports the negotiated maximum 
outgoing Datagram payload size and discards oversized writes as required by the 
WebTransport specification.


Blink component
Blink>Network>WebTransport


Web Feature ID
webtransport


Motivation
The original WebTransport Datagram API exposes only a single writable stream, 
preventing applications from independently scheduling different classes of 
latency-sensitive messages. The newer API allows applications such as games, 
remote-interaction systems, and real-time media applications to create multiple 
Datagram writables and prioritize urgent data over less time-sensitive data 
while preserving FIFO ordering within each writable. Implementing this API also 
resolves WebTransport Datagram interoperability failures included in Interop 
2026.


Initial public proposal
https://github.com/w3c/webtransport/issues/451


Goals for experimentation
None


Requires code in //chrome?
False


Tracking bug
https://issues.chromium.org/issues/547572475


Availability expectation
The feature is expected to be available across major browsers as part of the 
W3C WebTransport specification. Firefox implements the Datagram writable and 
prioritization APIs, and WebKit has landed an implementation that is currently 
in development.


Adoption expectation
Adoption is expected primarily among latency-sensitive WebTransport 
applications, including games, remote-interaction systems, and real-time media. 
Applications that need multiple independently prioritized Datagram queues are 
expected to begin adopting the API within 12 months of broad browser 
availability.


Adoption plan
Adoption is expected to happen organically through WebTransport documentation, 
examples, and Interop 2026 visibility. Existing applications do not need to 
migrate because the existing datagrams.writable API remains available.


Estimated milestones

No milestones specified



Anticipated spec changes

Open questions about a feature may be a source of future web compat or interop 
issues. Please list open issues (eg links to known github issues in the project 
for the feature specification) whose resolution may introduce web 
compat/interop risk (eg, changing to naming or structure of the API in a 
non-backward-compatible way).
No API-shape changes are currently anticipated. The WebTransport Working Group 
may further clarify scheduling boundaries and priority arbitration between 
streams and Datagrams in the same send group. Such clarification is expected to 
affect scheduling behavior only, not the exposed API.


Link to entry on the Chrome Platform Status
https://chromestatus.com/feature/5183354944225280?gate=5120520646426624


This intent message was generated by Chrome Platform Status.

-- 
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 [email protected].
To view this discussion visit 
https://groups.google.com/a/chromium.org/d/msgid/blink-dev/6a920d86.e8a51b51.6abb3.0299.GAE%40google.com.

Reply via email to