[tkz1312]

Haskell really shines when you want to write high level, declarative code. Performance when using this style is generally fine for CLI / web backend style stuff. It has the tools to write pretty fast low level code, but they’re fairly clunky and if that’s all you want to write it’s probably not going to be the best tool for the job. They’re pretty nice if you have a few focused hotspots you need to optimize.

It has pretty nice CPU profiling tools, so finding and optimizing CPU hotspots is fairly pleasant. Tracking down rouge memory leaks (which lazy evaluation makes more likely) on the other hand can be extremely frustrating.

If you look at the benchmarks game results [1], the fastest haskell implementations are generally between 2 and 5 times slower than the fastest c versions, and will be written in a highly imperative style.

[1]: https://benchmarksgame-team.pages.debian.net/benchmarksgame/...