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WebAssembly proposals

Active proposals

Proposals follow this process document.

Phase 5 - The Feature is Standardized (WG)

These proposals have not yet been merged to the spec. Merged proposals are listed in Finished Proposals.

Proposal Champion

Phase 4 - Standardize the Feature (WG)

Proposal Champion
Tail call Andreas Rossberg

Phase 3 - Implementation Phase (CG + WG)

Proposal Champion
Multiple memories Andreas Rossberg
Custom Annotation Syntax in the Text Format Andreas Rossberg
Memory64 Sam Clegg
Exception handling Heejin Ahn
Web Content Security Policy Francis McCabe
Branch Hinting Yuri Iozzelli
Extended Constant Expressions Sam Clegg
Relaxed SIMD Marat Dukhan & Zhi An Ng
Typed Function References Andreas Rossberg
Garbage collection Andreas Rossberg
Threads Conrad Watt
JS Promise Integration Ross Tate and Francis McCabe
Type Reflection for WebAssembly JavaScript API Ilya Rezvov

Phase 2 - Proposed Spec Text Available (CG + WG)

Proposal Champion
ECMAScript module integration Asumu Takikawa & Ms2ger
Relaxed dead code validation Conrad Watt and Ross Tate
Numeric Values in WAT Data Segments Ezzat Chamudi
Instrument and Tracing Technology Richard Winterton

Phase 1 - Feature Proposal (CG)

Proposal Champion
Type Imports Andreas Rossberg
Component Model Luke Wagner
WebAssembly C and C++ API Andreas Rossberg
Extended Name Section Andrew Scheidecker
Flexible Vectors Petr Penzin
Call Tags Ross Tate
Stack Switching Francis McCabe & Sam Lindley
Constant Time Sunjay Cauligi, Garrett Gu, John Renner, Hovav Shacham, Deian Stefan, Conrad Watt
JS Customization for GC Objects Asumu Takikawa
Memory control Deepti Gandluri
Reference-Typed Strings Andy Wingo
Profiles Andreas Rossberg

Phase 0 - Pre-Proposal (CG)

Proposal Champion

Implementation status

Roadmap is available on

Contributing new proposals

Please see Contributing to WebAssembly for the most up-to-date information on contributing proposals to standard.


Tracking WebAssembly proposals



Code of conduct





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