The best concurrency libraries, according to hackers
11 concurrency libraries were recommended on Hacker News between November 2025 and November 2026. We rank them by how many separate people recommend each one, and 2 earn the Hacker Approved badge.
Top picks
The two most recommended concurrency libraries with the badge. Each figure is one person. RecommendsCriticizes One comment
Ergonomic and easy to read
Recommended for its ergonomic, typed effects system that makes concurrency and async code more robust and easier to read. One critic calls it all complexity and no guarantees.
Better alternative to asyncio
Python async library whose structured concurrency makes code simpler and more predictable than asyncio, with a thoughtful design and an excellent tutorial.
All 11 concurrency libraries, ranked
Select a column heading to sort. Approval share is recommenders out of everyone who gave an opinion; the tick on each bar marks the 2 to 1 line the badge needs. Months counts the months, out of 13, in which someone recommended it.
| Rank | |||||||
|---|---|---|---|---|---|---|---|
| 1 | Tokio | 57 | 45 | 56% | 12 | — | — |
| 2 | Akka | 12 | 9 | 57% | 7 | — | — |
| 3 | ZIO | 11 | 2 | 85% | 9 | — | Approved |
| 4 | Trio Python library | 10 | 0 | 100% | 8 | — | Approved |
| 5 | core.async | 9 | 4 | 69% | 6 | — | — |
| Tied 6 | gevent | 7 | 5 | 58% | 4 | — | — |
| Tied 6 | Python asyncio | 7 | 17 | 29% | 4 | — | — |
| Tied 6 | Kotlin coroutines | 7 | 4 | 64% | 4 | — | — |
| 9 | Node.js worker_threads | 6 | 5 | 55% | 3 | — | — |
| Tied 10 | Microsoft Orleans | 5 | 2 | 71% | 4 | — | — |
| Tied 10 | Grand Central Dispatch | 5 | 2 | 71% | 4 | — | — |
How we rank
Rank is the number of separate people who recommend a product in a Hacker News comment over the past year. Someone who praises the same concurrency library in five threads counts once.
The badge goes to concurrency libraries that at least 10 people recommend, with recommenders outnumbering critics at least 2 to 1, recommended in at least 4 of the 13 months.
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