Wasmtime
Hacker ApprovedThe most recommended of 5 webassembly runtimes
Developers pick Wasmtime to run WebAssembly with fine-grained sandbox limits and wide standards support, for plugins and server workloads. Critics say its fuel metering adds a large performance penalty.
Developers pick Wasmtime to run WebAssembly with fine-grained sandbox limits and wide standards support, for plugins and server workloads. Critics say its fuel metering adds a large performance penalty.
20 people gave an opinion
- recommend it
- 16
- criticize it
- 4
- approval share
- 80%
Recommended in 7 of 13 months
- November 2025: not recommended
- December 2025: recommended
- January 2026: recommended
- February 2026: not recommended
- March 2026: recommended
- April 2026: not recommended
- May 2026: recommended
- June 2026: recommended
- July 2026: recommended
- August 2026: not recommended
- September 2026: not recommended
- October 2026: recommended
- November 2026: not recommended (month in progress)
Why it carries the badge
- 16 people recommend itNeeds 10 or more, met.
- 4 recommenders for every criticNeeds 2 to 1 or better, met.
- Recommended in 7 of 13 monthsNeeds 4 or more, met.
The same three rules apply to every product, and the badge can’t be bought. How the badge works
What people say about it
The reasons people give, with the number of comments that give each one. Open a reason to read what they said.
Why people recommend it
Each mark is one comment
Good for sandboxed plugins
“I've been having great luck with wasmtime and wasm32-wasip3 for writing sandboxed plugins”
Comment from 9 Oct 2026 in “MXC - a sandboxed code execution system” “If you need plugins, embed v8, quickjs or wasmtime/wasmer/etc.”
Comment from 1 Oct 2026 in “Pi 1.0” “run server or plugin workloads on wasmtime or wasmer”
Comment from 8 Mar 2026 in “Notes on Writing WASM” Fine-grained sandbox limits and controls
“Wasmtime also lets you do things like epoch-based interruption, 'gas' for limiting instruction count, memory limits, and a bunch of other things that give you tons of control over the sandbox.”
Comment from 31 Jan 2026 in “Show HN: Amla Sandbox – WASM bash shell sandbox for AI agents” “Wasmtime's "fuel" feature is not something you can do with containers”
Comment from 12 Jun 2026 in “WASI 0.3.0 Released” Strong isolation and security posture
“It's lightweight, capability-secured, services start up way faster, smaller overhead than VMs, better isolation than containers”
Comment from 25 Jul 2026 in “GC and Exceptions in Wasmtime” “with a security posture that beats pretty much anything widely deployed”
Comment from 1 Oct 2026 in “Pi 1.0” Early support for newest WASI standards
“I've been having great luck with wasmtime and wasm32-wasip3 for writing sandboxed plugins”
Comment from 9 Oct 2026 in “MXC - a sandboxed code execution system” “only wasmtime seems to fully support wasm32-wasip2”
Comment from 9 Jan 2026 in “What Happened to WebAssembly”
What people warn about
Each mark is one comment
Fuel metering slows applications noticeably
“Wasmtime's fuel metering makes applications horribly slow.”
Comment from 29 Nov 2025 in “Wasmtime Bactched Fuel Increments” “for a sweet sweet 30% performance penalty”
Comment from 20 Jun 2026 in “Bun has an open PR adding shared-memory threads to JavaScriptCore”
Other webassembly runtimes people recommend
The four most recommended other webassembly runtimes, with the same counts for each, so you can compare like for like. The tick on each bar marks the 2 to 1 line the badge needs.
| Product | Recommend | Criticize | Approval | Months | Owned | Badge |
|---|---|---|---|---|---|---|
| WasmtimeThis page | 16 | 4 | 80% | 7 | — | Approved |
| Pollen WASM runtime | 10 | 0 | 100% | 1 | — | — |
| Pollen | 8 | 2 | 80% | 3 | — | — |
| wazero | 7 | 1 | 88% | 5 | — | — |
| Popcorn | 5 | 0 | 100% | 2 | — | — |
What people said
19 of the 21 comments that mention it, newest first. Each links to the original comment.
“I'd consider getting your workflow running in wasm (in wasmtime on the server)”
“I tend to use Wasmtime, V8, WAMR, and browsers”
“I've been having great luck with wasmtime and wasm32-wasip3 for writing sandboxed plugins”
“with a security posture that beats pretty much anything widely deployed”
“If you need plugins, embed v8, quickjs or wasmtime/wasmer/etc.”
“It's lightweight, capability-secured, services start up way faster, smaller overhead than VMs, better isolation than containers”
“Learning what wasmtime is and how it works is also illuminating”
“for a sweet sweet 30% performance penalty”
“Wasmtime implements a remote debugging server, so that you can debug guest programs”
“Wasmtime's "fuel" feature is not something you can do with containers”
“even BigGo failed me on websocket conns on both wasmtime and wazero (connects and gets into an inf loop on reply)”
“run server or plugin workloads on wasmtime or wasmer”
“Wasmtime also lets you do things like epoch-based interruption, 'gas' for limiting instruction count, memory limits, and a bunch of other things that give you tons of control over the sandbox.”
“Being backed by wasmtime and the rather strict Rust compiler is definitely a boon here!”
“only wasmtime seems to fully support wasm32-wasip2”
“JCO/wasmtime: 314µs / 13ms”
“GOOS=wasip1 GOARCH=wasm go build -o main.wasm main.go wasmtime main.wasm”
“I can get a Python interpreter to run in wasmtime, but that doesn't have the Pyodide goodies like Micropip etc.”
“Wasmtime's fuel metering makes applications horribly slow.”
Counts come from 1,795,640 Hacker News comments, November 2025 to November 2026. How we count. Report a mistake.