Boa JavaScript engine

What hackers pick instead

• V8 JavaScript engineFast, widely deployed JavaScript engine from Google that people praise for performance and sandboxing. Caveats: large, complex C++ codebase with an unstable embedding API and recurring JIT-related security bugs.59recommend
• QuickJSSmall, self-contained, fast C JavaScript engine by Fabrice Bellard that matches almost all of ES2025 and is easy to embed. Critics say it is much slower than JIT engines such as V8.33recommend
• MicroQuickJSTiny JavaScript engine for microcontrollers and embedding, praised for its small memory use and sandboxing. Main caveat: it implements only a subset of JavaScript close to ES5.19recommend
• JavaScriptCoreApple's JavaScript engine, used by WebKit and Bun, with well-tuned JIT performance and a long track record on consumer devices.14recommend
• SpiderMonkeyMozilla's JavaScript engine that people find well maintained and self-contained; the most common caveat is that it is slower than V8.8recommend

Every quote

The 25 most detailed of 26 comments. Each links to the original.

1. I love how supremely easy it looks to embed in normal Rust apps without a complicated build script.

   Recommends · Nov 2025 · in “Boa: A standard-conforming embeddable JavaScript engine written in Rust”

2. plenty of Rust projects have found good use for it as they find it easy to embed and use

   Recommends · Nov 2025 · in “Boa: A standard-conforming embeddable JavaScript engine written in Rust”

3. each request is almost guaranteed to be slower because V8 will be faster than Boa

   Mixed · Dec 2025 · in “Show HN: Titan – JavaScript-first framework that compiles into a Rust server”

4. we caught up with the top engines but we surpassed them when working on Temporal

   Recommends · Nov 2025 · in “Boa: A standard-conforming embeddable JavaScript engine written in Rust”

5. The Temporal in rust release happening in Chrome & others is so cool!

   Recommends · Nov 2025 · in “Boa: A standard-conforming embeddable JavaScript engine written in Rust”

6. I really appreciate the clear and detailed project description

   Recommends · Nov 2025 · in “Boa: A standard-conforming embeddable JavaScript engine written in Rust”

7. This sounds really well architected and extensible.

   Recommends · Nov 2025 · in “Boa: A standard-conforming embeddable JavaScript engine written in Rust”

8. Oh my god, that's so easy to embed.

   Recommends · Nov 2025 · in “Boa: A standard-conforming embeddable JavaScript engine written in Rust”

9. Seems like a nice team and project.

   Recommends · Nov 2025 · in “Boa: A standard-conforming embeddable JavaScript engine written in Rust”

10. V8-jitless is in the benchmarks and even then still blows it away

    Criticizes · Nov 2025 · in “Boa: A standard-conforming embeddable JavaScript engine written in Rust”

11. Boa is very very slow compared to JIT compiled JavaScript

    Criticizes · Dec 2025 · in “Show HN: Titan – JavaScript-first framework that compiles into a Rust server”

12. Boa doesn't perform well on desktop in debug mode

    Criticizes · Nov 2025 · in “Ask HN: What Are You Working On? (Nov 2025)”

13. But it uses a slow JS engine called Boa.

    Criticizes · Dec 2025 · in “Show HN: Titan – JavaScript-first framework that compiles into a Rust server”

14. People who just want to run JavaScript code where performance isn't such a big concern would prefer something like Boa

    Recommends · Nov 2025 · in “Boa: A standard-conforming embeddable JavaScript engine written in Rust”

15. I think it would be cool to have a highly performant and conformant Rust JavaScript engine.

    Recommends · Nov 2025 · in “Boa: A standard-conforming embeddable JavaScript engine written in Rust”

16. One optimization that they have that Boa needs to implement is ropes for our string type

    Mixed · Nov 2025 · in “Boa: A standard-conforming embeddable JavaScript engine written in Rust”

17. That in combination with boa_engine lets me build a statically linked executable

    Recommends · Feb 2026 · in “The JavaScript Oxidation Compiler”

18. the project was progressing pretty slowly from what people were expecting

    Mixed · Nov 2025 · in “Boa: A standard-conforming embeddable JavaScript engine written in Rust”

19. It has excellent standards conformance, but terrible performance.

    Mixed · Nov 2025 · in “Dillo, a multi-platform graphical web browser”

20. Awesome! I'm always on the lookout for embeddable JS engines.

    Recommends · Nov 2025 · in “Boa: A standard-conforming embeddable JavaScript engine written in Rust”

21. I could see myself using something like this instead of Lua

    Recommends · Nov 2025 · in “Boa: A standard-conforming embeddable JavaScript engine written in Rust”

22. This project is pretty cool

    Recommends · Nov 2025 · in “Boa: A standard-conforming embeddable JavaScript engine written in Rust”

23. not seeing their main competitors in a benchmark is a massive red flag to me

    Criticizes · Nov 2025 · in “Boa: A standard-conforming embeddable JavaScript engine written in Rust”

24. it fails on a small number of test cases, on v0.21 that is ~900 out of ~50k

    Criticizes · Nov 2025 · in “Boa: A standard-conforming embeddable JavaScript engine written in Rust”

25. Boa absolutely destroys v8 here though

    Criticizes · Nov 2025 · in “Boa: A standard-conforming embeddable JavaScript engine written in Rust”