# mimalloc

22 Hacker News commenters recommended mimalloc and 7 criticized it, November 2025 to November 2026. It was recommended in 9 of 13 months. It meets the Hacker Approved badge rule.

**Verdict:** Recommended as a fast, easy drop-in malloc replacement with many tuning knobs, though critics report high memory use.

## Why people recommend it

- Fast, close to glibc speed (5 comments): "Switching to mimalloc improved performance by 20x, very close to what glibc offers by default" ([source](https://news.ycombinator.com/item?id=49134609)) "mimalloc (which is a high performance allocator, at least as fast as the glibc allocator)" ([source](https://news.ycombinator.com/item?id=49481335)) "modern allocators like mimalloc or jemalloc easily outperformed modern GCs of Java" ([source](https://news.ycombinator.com/item?id=45952260))
- Easy drop-in replacement, no code changes (4 comments): "Luckily that one is fairly easy to fix with installing mimalloc and deploying the hijack dll" ([source](https://news.ycombinator.com/item?id=49873975)) "plugging in mimalloc or jemalloc will be much less work, and much less error prone" ([source](https://news.ycombinator.com/item?id=49767422)) "Mi-malloc is the better choice if you must preload a library" ([source](https://news.ycombinator.com/item?id=46456692))
- Aggressive memory reclaim, stable footprint (3 comments): "Dip's memory, using mimalloc, stabilizes at ~60 MB post request completion no matter how many requests you throw at it." ([source](https://news.ycombinator.com/item?id=50271512)) "Agree with you on mimalloc. It can even be configured to be aggressive in memory reclaim at the cost of performance." ([source](https://news.ycombinator.com/item?id=49137278)) "mimalloc aggressively reclaims space and it benefits the use case in our Dip database built on rust." ([source](https://news.ycombinator.com/item?id=50267286))
- Many configurable knobs (2 comments): "Agree with you on mimalloc. It can even be configured to be aggressive in memory reclaim at the cost of performance." ([source](https://news.ycombinator.com/item?id=49137278)) "The nice thing about mimalloc is that there are a ton of configurable knobs available via env vars." ([source](https://news.ycombinator.com/item?id=47403583))

## What people warn about

- Uses more memory than expected (5 comments): "we had problem with mimalloc memory usage with pthread enabled" ([source](https://news.ycombinator.com/item?id=46340169)) "the additional memory usage was a very real inconvenience" ([source](https://news.ycombinator.com/item?id=49135679)) "mimalloc just consumed memory like crazy" ([source](https://news.ycombinator.com/item?id=47415980))
- Speed claims did not hold up (4 comments): "Last time I checked mimalloc which was admittedly a while ago, probably 5 years, it was noticebly worse" ([source](https://news.ycombinator.com/item?id=47403260)) "mimalloc definitely made claims that could not be reproduced" ([source](https://news.ycombinator.com/item?id=47406528)) "it wasn't faster by much, and had pretty bad worst cases" ([source](https://news.ycombinator.com/item?id=47405045))
- Seen as a black box (2 comments): "big general-purpose allocators like jemalloc or mimalloc are usually a bandaid to somewhat salvage a failed memory management strategy" ([source](https://news.ycombinator.com/item?id=48519858)) "Standard options like jemalloc and mimalloc are incredibly fast, but they act as black boxes." ([source](https://news.ycombinator.com/item?id=47520808))

## Alternatives hackers recommend

- [jemalloc](https://hackerapproved.com/p/jemalloc.md): 34 recommend
- [Bumpalo Rust crate](https://hackerapproved.com/p/bumpalo.md): 8 recommend
- [tcmalloc](https://hackerapproved.com/p/tcmalloc.md): 7 recommend

## Cite as

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