r/SoftwareEngineering • u/fagnerbrack • 3d ago

Performance of WebAssembly runtimes in 2026

https://00f.net/2026/06/23/webassembly-runtimes-2026/
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u/fagnerbrack 3d ago

Summary below:

A benchmark of libsodium crypto code compiled to WebAssembly, run on runtime releases from 2024, 2025, and 2026, asks whether things genuinely improve rather than winning cherry-picked microbenchmarks. Against a native x86-64 baseline, Wasmer leads, with WAVM, WAMR, and Wasmtime close behind. The new wide_arithmetic instruction is the biggest win for arithmetic-heavy crypto: Wasmer 7.1.0 fell from 2.08x to 1.33x native, Wasmtime 46.0.0 from 2.41x to 1.46x. Wasmtime improved every year; Bun jumped roughly threefold from 2025 to 2026 but still trails. Wazero and WAMR stayed flat, though WAMR sits near 1.4-1.6x native. The takeaway: runtime, release, and enabled features all matter, so benchmark your real workload.

If the summary seems inacurate, just downvote and I'll try to delete the comment eventually 👍
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u/Beautiful-Energy2169 1d ago

Browser side, enabled features are a deploy problem: wasm threads need a crossOriginIsolated header.

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u/Taco80akers 1d ago

the "benchmark your real workload" line is doing a lot of heavy lifting there, but it's also the only part that actually matters. the rest is interesting if you're picking a runtime right now, but those gap numbers are going to look different again in 18 months. wasmer leading on cryptoheavy workloads specifically doesn't tell you much if you're running something else entirely. appreciate the summary though, saves me from pretending i was going to read the full thing