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This repository hosts the Web IDL Standard.

Code of conduct

We are committed to providing a friendly, safe, and welcoming environment for all. Please read and respect the WHATWG Code of Conduct.


Good first issues are labeled as a short good first issue.

IDL generally follows the WHATWG Contributor Guidelines and WHATWG Committer Guidelines, except as otherwise noted.


The specification is written in Bikeshed, plus the Ecmarkup tags <emu-val>, <emu-t>, and <emu-nt>.

Building "locally"

For quick local iteration, run make. To verify your changes locally, run npm install and make deploy. See more in the WHATWG Contributor Guidelines.

Filing issues elsewhere

Breaking changes should be filed against:

Syntax changes should be filed against the following parsers: