The reference for WebAssembly runtimes.
Independent benchmarks, feature support and proposal performance. Every number links to the run that produced it.
Fastest execution 2026-10-25 · per invocation
Geometric mean over measured application workloads · AMD Ryzen 7800X3D
23 runtimes & engines tracked
145 measured contracts
1.95M latest-version timing samples · all machines
12.9M all-version timing samples · all machines
51 features tracked
3 machines
What's inside
One place to answer “which runtime, and why?”
Benchmarks →
Compilation, instantiation, execution, memory and machine code across real programs and microbenchmarks.
History →
Every metric over time, with source revisions, recorded gaps and a fixed comparison-engine baseline.
Features →
Released engine compatibility, official suite results and feature performance.
Proposals
Beyond the checkbox.
Each major proposal has a permanent page combining status, adoption and measured performance.
SIMDPhase 5 · Wasm 2.0 How much faster does SIMD actually make Wasm?WasmGCPhase 5 · Wasm 3.0 What is the allocation throughput and memory behavior of WasmGC implementations?Memory64Phase 5 · Wasm 3.0 What does 64-bit addressing cost compared to a matched 32-bit build?ThreadsPhase 4 How does throughput scale with worker count, and what does each worker cost?
Methodology
Built to be checked.
Every number is reproducible
Each result resolves to a run record with versions, flags, machine, harness revision and the exact command.
Scope is always visible
Hardware, snapshot and workload set travel with every comparison, chart and export.
Missing is never zero
Unsupported, failed, crashed and not-measured stay distinct. Incorrect results get no performance credit.
Recent changes
All history and change reportsWhat moved this quarter.
Missing a runtime or a program?
wasm.fyi is open. Submit a runtime adapter, add a workload, or reproduce a result on your own hardware.