Clone this repo:
  1. 9d789ca [spec] Makefile tweak by Andreas Rossberg · 8 days ago master
  2. 40d27eb Normative: Re-exported host functions are numbered by Daniel Ehrenberg · 13 days ago
  3. 59f6199 [test] JS API tests for caching and function names by Daniel Ehrenberg · 13 days ago
  4. a25083a [interpreter] Add number grammar to README by Andreas Rossberg · 2 weeks ago
  5. 378fcb2 [interpreter] Remove remnants of assert_soft_invalid (#641) by Andreas Rossberg · 2 weeks ago

Build Status


This repository holds the sources for the WebAssembly draft specification (to seed a future WebAssembly Working Group), a reference implementation, and the official testsuite.

A formatted version of the spec is available here:,

Participation is welcome. Discussions about new features, significant semantic changes, or any specification change likely to generate substantial discussion should take place in the WebAssembly design repository first, so that this spec repository can remain focused. And please follow the guidelines for contributing.