SpiderMonkey
Shares rank 6 of 7 JavaScript engines by recommenders
Mozilla's JavaScript engine that people find well maintained and self-contained; the most common caveat is that it is slower than V8.
Mozilla's JavaScript engine that people find well maintained and self-contained; the most common caveat is that it is slower than V8.
15 people gave an opinion
- recommend it
- 8
- criticize it
- 7
- approval share
- 53%
Recommended in 6 of 13 months
- November 2025: not recommended
- December 2025: not recommended
- January 2026: recommended
- February 2026: not recommended
- March 2026: recommended
- April 2026: recommended
- May 2026: recommended
- June 2026: not recommended
- July 2026: not recommended
- August 2026: recommended
- September 2026: recommended
- October 2026: not recommended
- November 2026: not recommended (month in progress)
Why it doesn’t carry the badge
- 8 people recommend itNeeds 10 or more, not met.
- 1.1 recommenders for every criticNeeds 2 to 1 or better, not met.
- Recommended in 6 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
Works well with little regression
“SpiderMonkey works, and presumably is fairly self-contained”
Comment from 13 Apr 2026 in “Servo is now available on crates.io” “SpiderMonkey did the best with almost no regression”
Comment from 6 Apr 2026 in “A tail-call interpreter in (nightly) Rust”
What people warn about
Each mark is one comment
Written in C++ rather than Rust
“it's still disappointing that the script engine uses SpiderMonkey, which is purely C++”
Comment from 13 Apr 2026 in “Servo is now available on crates.io” “Servo uses mozjs which is just rust bindings for SpiderMonkey which is still C++”
Comment from 17 Sep 2026 in “One year of sponsored Servo development” Slower than V8
“SpiderMonkey seems... not up there compared to the other 2”
Comment from 4 Jan 2026 in “JavaScript engines zoo – Compare every JavaScript engine” “SpiderMonkey is also now just quite a bit slower than V8”
Comment from 4 Jan 2026 in “JavaScript engines zoo – Compare every JavaScript engine”
Other JavaScript engines people recommend
The four most recommended other JavaScript engines, 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 |
|---|---|---|---|---|---|---|
| V8 JavaScript engine | 59 | 36 | 62% | 12 | — | — |
| QuickJS | 33 | 8 | 80% | 10 | — | Approved |
| MicroQuickJS | 19 | 8 | 70% | 3 | — | — |
| JavaScriptCore | 14 | 5 | 74% | 9 | — | Approved |
| SpiderMonkeyThis page | 8 | 7 | 53% | 6 | — | — |
What people said
15 of the 16 comments that mention it, newest first. Each links to the original comment.
“beautiful, long expository comments explaining not only what, but why design choices have been made”
“Servo uses mozjs which is just rust bindings for SpiderMonkey which is still C++”
“it sounds like maybe they should consider using another JavaScript engine if it's causing problems”
“The technical debt in SpiderMonkey (at that time, anyway) was eye-watering.”
“there's still no good Node-compatible wrapper for SpiderMonkey”
“it appears they are keeping up to date with security features”
“SpiderMonkey works, and presumably is fairly self-contained”
“it's still disappointing that the script engine uses SpiderMonkey, which is purely C++”
“SpiderMonkey did the best with almost no regression”
“can work with V8, Javascript, SpiderMonkey, QuickJS, Hermes, etc.”
“SpiderMonkey is also now just quite a bit slower than V8”
“SpiderMonkey seems... not up there compared to the other 2”
“except v8/spidermonkey (and the now defunct chakra) have PTC.”
“spidermonkey is an insecure time bomb”
“V8/JSC/SM, but they don't exactly fit with the "lightweight ethos"”
Counts come from 1,795,640 Hacker News comments, November 2025 to November 2026. How we count. Report a mistake.