# SpiderMonkey

8 Hacker News commenters recommended SpiderMonkey and 7 criticized it, November 2025 to November 2026. It was recommended in 6 of 13 months.

**Verdict:** Mozilla's JavaScript engine that people find well maintained and self-contained; the most common caveat is that it is slower than V8.

## Why people recommend it

- Works well with little regression (2 comments): "SpiderMonkey works, and presumably is fairly self-contained" ([source](https://news.ycombinator.com/item?id=47752151)) "SpiderMonkey did the best with almost no regression" ([source](https://news.ycombinator.com/item?id=47657047))

## What people warn about

- Written in C++ rather than Rust (2 comments): "it's still disappointing that the script engine uses SpiderMonkey, which is purely C++" ([source](https://news.ycombinator.com/item?id=47752045)) "Servo uses mozjs which is just rust bindings for SpiderMonkey which is still C++" ([source](https://news.ycombinator.com/item?id=49739534))
- Slower than V8 (2 comments): "SpiderMonkey seems... not up there compared to the other 2" ([source](https://news.ycombinator.com/item?id=46486993)) "SpiderMonkey is also now just quite a bit slower than V8" ([source](https://news.ycombinator.com/item?id=46491752))

## Alternatives hackers recommend

- [V8 JavaScript engine](https://hackerapproved.com/p/v8.md): 59 recommend
- [QuickJS](https://hackerapproved.com/p/quickjs.md): 33 recommend
- [MicroQuickJS](https://hackerapproved.com/p/microquickjs.md): 19 recommend
- [JavaScriptCore](https://hackerapproved.com/p/javascriptcore.md): 14 recommend
- [Boa JavaScript engine](https://hackerapproved.com/p/boa-javascript-engine.md): 14 recommend

## Cite as

Hacker Approved, "SpiderMonkey", https://hackerapproved.com/p/spidermonkey/ (counts from 1,795,640 Hacker News comments, November 2025 to November 2026).