WASI 0.3 (Preview 3)

A dated reading of what is claimed, reported, and independently verified in the current evidence.

Current reading

Readiness band and full integer triple

AI-assisted assembly · derived results

Readiness band

Ready

Primary summary from verified readiness

Evidence strength Strong

Decision

Human editorial judgment · 2026-08-20

Track; not yet

Why: Native async is a genuine architectural milestone and momentum is high, but the release is only weeks old, flag-gated on bleeding-edge runtimes, offers concurrency without parallelism, and is explicitly pre-1.0 — adoption risk outweighs benefit for production edge workloads today.
Next: Spike a single non-critical component against Wasmtime 45/46 with WASI 0.3 async to measure real cold-start (p50/p95 with and without precompilation) and density vs the current Workers path; do not put production traffic on it before WASI 1.0.

Constraints

No named blocker is present in the current public projection.

Evidence summary

AI-assisted assembly

Counts and dates only. Raw signals, private excerpts, trust records, and internal corpus material are not published here.

Publication record

Revision 12