Roadmap
This roadmap is a living document representing projected timelines for WASI releases. Goals and projections are provisional and subject to revision.
WASI 0.2 releases
WASI 0.2 point releases occur every two months, on the first Thursday of that month, on a release train model—a regular cadence in which releases are published regardless of the enhancements and fixes that are "ready for the train." Point releases include smaller features and big fixes, while major features and breaking changes are generally reserved for major versions.
Previous releases:
| WASI version | Date |
|---|---|
| 0.2.1 | 2024-08-01 |
| 0.2.2 | 2024-10-03 |
| 0.2.3 | 2024-12-05 |
| 0.2.4 | 2025-02-06 |
Future releases:
| WASI version | Date |
|---|---|
| 0.2.5 | 2025-04-03 |
The release train for WASI 0.2 will end following the release of WASI 0.3.0.
Upcoming WASI 0.3 releases
WASI 0.3.0 is planning to release at the end of March 2025, adding native async support to the Component Model and refactoring WASI 0.2 interfaces to take advantage of native async.
Native async will enable any component-level function to be implemented and/or called asynchronously, with asynchrony implemented at the level of the Canonical ABI. This includes explicit stream<T> and future<T> types for use anywhere in function parameters and results.
When WASI 0.3 is launched, implementations may continue to support 0.2, either by implementing 0.3 alongside it, or by virtualizing (polyfilling) 0.2 in terms of 0.3.
After WASI 0.3.0 is released, a series of incremental and backwards-compatible 0.3.x releases will occur on the release train model. These point releases are expected to include:
- Cancellation automatically integrated with language idioms
- Specialization of
tuple<stream<u8>,future<result<trailers, http-error>>>existing in 0.3.0 - Stream optimization with Canonical ABI built-ins for forwarding/splicing, skipping/writing-zeroes, stream data segment, and lulls
- Caller-supplied buffers with more zero-copy in more scenarios
- Threads: first cooperative, then preemptive
You can find more information in the WebAssembly CG presentation from February 2025.
Project timeline
The provisional timeline for WASI releases is as follows:
