# MicroQuickJS

Hacker Approved page: https://hackerapproved.com/p/microquickjs/

14 people recommended MicroQuickJS in Hacker News comments, 4 had mixed feelings and 7 criticized it, November 2025 to October 2026. It was recommended in 3 of 12 months, in 5 threads. It does not meet the Hacker Approved badge rule.

11 of the 14 people who recommend it commented in one thread, “Fabrice Bellard Releases MicroQuickJS”.

**Verdict:** Tiny 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.

Summary written by Claude from 26 comments. It was written before the November 2026 recount, and 25 of those comments still count.

## Why people recommend it

- Very small memory footprint (3 comments in the sample): "Needing only 10K of RAM, it looks like a much better solution to CircuitPython" ([source](https://news.ycombinator.com/item?id=46368661)) "would be a killer replacement for micro/circuitpython for embedded devices" ([source](https://news.ycombinator.com/item?id=46369148)) "the fact that he can optimize a js engine down to 10kb of ram is wild" ([source](https://news.ycombinator.com/item?id=46379644))
- Restricted subset avoids unneeded features (3 comments in the sample): "none of the things which are impossible in this subset are things I would do in the course of normal programming anyway" ([source](https://news.ycombinator.com/item?id=46368068)) "restricting it this way for embedded systems will result in something that sparks joy" ([source](https://news.ycombinator.com/item?id=46367946)) "I'm really happy to see the stricter mode" ([source](https://news.ycombinator.com/item?id=46375531))
- Easy to embed in existing software (2 comments in the sample): "If you have some software that’s somewhat rigid you could make it scriptable by linking microquickjs." ([source](https://news.ycombinator.com/item?id=46385520)) "quickjs/mquickjs are good at embedding but nowhere close to luajit in terms of speed" ([source](https://news.ycombinator.com/item?id=47016678))
- Sandboxing with memory and time limits (2 comments in the sample): "a useful sandbox in that you can robustly limit both the memory and time allowed" ([source](https://news.ycombinator.com/item?id=46368358)) "shouldn't be escapable, in theory, given the memory model" ([source](https://news.ycombinator.com/item?id=46494287))

## What people warn about

- Only a subset of ES5 (2 comments in the sample): "I don't think you can transpile arbitrary TS in mqjs's JS subset." ([source](https://news.ycombinator.com/item?id=46370868)) "it's not a full implementation of even ES5" ([source](https://news.ycombinator.com/item?id=46369168))

## Other JavaScript engines people recommend

- [V8 JavaScript engine](https://hackerapproved.com/p/v8/): 39 recommend, 17 mixed, 33 criticize
- [QuickJS](https://hackerapproved.com/p/quickjs/): 24 recommend, 7 mixed, 6 criticize
- [Boa JavaScript engine](https://hackerapproved.com/p/boa-javascript-engine/): 9 recommend, 5 mixed, 4 criticize
- [JavaScriptCore](https://hackerapproved.com/p/javascriptcore/): 8 recommend, 6 mixed, 4 criticize

## The badge

A product earns the Hacker Approved badge when at least 10 people recommend it, recommenders outnumber critics at least 2 to 1 (mixed feelings count toward neither side), it was recommended in at least 4 of the 12 months and in at least 5 different threads, and no single thread supplies more than half of the people who recommend it. Health and money products are never badged.

## Cite as

Hacker Approved, "MicroQuickJS", https://hackerapproved.com/p/microquickjs/ (14 recommend, 4 mixed, 7 criticize; Hacker News comments, November 2025 to October 2026).

Counts updated 2 Nov 2026, with data through October 31, 2026.