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Top 23 Concurrency Open-Source Projects
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Project mention: Yazi: Fast terminal file manager written in Rust, based on async I/O | news.ycombinator.com | 2026-09-20
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Project mention: Show HN: Sycamore – next gen Rust UI library powered by fine-grained reactivity | news.ycombinator.com | 2026-04-01
I looked briefly, but is anyone aware of the differences between Yew[1] and Sycamore[2]? Presumably they are both Elm-influenced Rust web UI libraries named after trees, but it's unclear to me why I should use one versus the other.
1. https://github.com/yewstack/yew
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Project mention: How to Build a Real-Time Chat App with WebSockets (And Why It Works) | dev.to | 2026-03-19
PHP can handle WebSockets. Projects like Ratchet and Swoole exist for exactly this reason. The traditional PHP execution model — spin up a process per request, run the script, die — doesn't naturally fit persistent connections. But the ecosystem has evolved.
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Project mention: LMAX Disruptor – High Performance Inter-Thread Messaging Library | news.ycombinator.com | 2026-09-15
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Almost every single JavaScript package is on NPM. Being on NPM does not automatically increase your attack vectors. The vast majority of the npm attacks have been "Supply Chain Attacks"[1] where an upstream dependency is injected with malicious code, then automatically downloaded and executed when users update a package. If you look at Effect's package.json on GitHub[0], you'll see that they have several "devDependencies", but no regular "dependencies". That means, unless you are working on the package itself, using it does not require downloading any other packages whatsoever. Thus, Effect is not susceptible to any of the issues that you have read about in the news. The only way malicious code could be transported through the package would be if the maintainers suddenly became evil.
That being said, I don't use Effect and I think it's kind of overrated by the FP community. But, I appreciate the ideas behind it, and I felt the need to educate you about your needless fear of any library simply existing on NPM.
[0] https://github.com/Effect-TS/effect/blob/main/package.json
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Project mention: Standing on shoulders: the stack that makes Floci start in ~24ms | dev.to | 2026-05-21
Vert.x is the layer where Floci uses things directly. It's Netty with ergonomics: an event loop, a router, protocol-specific APIs for HTTP, DNS, TCP, WebSockets, gRPC, all sharing the same threading model.
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That's it. Everything else — async/await, actors, work-stealing executors, lock-free data structures — lives in the ecosystem (tokio, rayon, crossbeam, actix, etc.).
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Akka
A platform to build and run apps that are elastic, agile, and resilient. SDK, libraries, and hosted environments.
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Project mention: The PImpl idiom and the C++26 std:indirect type | news.ycombinator.com | 2026-07-24
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The BLoC (Business Logic Component) pattern is where serious teams land. Google's own Flutter team uses it internally. Nubank, one of the world's largest digital banks with 90 million customers, built its app on it. BMW runs it in production. The flutter_bloc package has logged over 1.4 million downloads on pub.dev. That's not hype. That's validation at scale.
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That's it. Everything else — async/await, actors, work-stealing executors, lock-free data structures — lives in the ecosystem (tokio, rayon, crossbeam, actix, etc.).
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That's it. Everything else — async/await, actors, work-stealing executors, lock-free data structures — lives in the ecosystem (tokio, rayon, crossbeam, actix, etc.).
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I would highly recommend using ORM's, with the caveat to know exactly when not to use them. Startups do not fall in that bucket.
1. Most of these advices are unfortunately impractical and incomplete for startups. A good Data Model is highly dependent on understanding the business requirements, data flows. Means unless you are repeating yourself in the same domain its really hard to come up with a good schema in first iteration.
2. Startups are in the mode of discovering the schema for most part
3. Deleting columns is harder than adding additional columns, no one takes that risk so everyone ends up with schema bloat
4. Once you go a little bigger you will realize that the integer based UUID are not that great of a choice. Those are separate tables which maintain those index counters and not part of your DDLs. They have their own set of issues with data merging, backups and recovery
For the OP, I looked at the repo (https://github.com/hatchet-dev/hatchet/blob/main/sql/schema/...) ,
1. seems like the schema has database functions - Thats a potential scaling issue, plus you are asking vertical only scalable component to do something which could have taken care by horizontally scalable component
2. TEXT datatype for pretty much every attribute - this is a footgun, you cant use them for indexes properly, in the absence of length checks they can be abused from client side
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Concurrent Ruby
Modern concurrency tools including agents, futures, promises, thread pools, supervisors, and more. Inspired by Erlang, Clojure, Scala, Go, Java, JavaScript, and classic concurrency patterns.
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NOTE:
The open source projects on this list are ordered by number of github stars.
The number of mentions indicates repo mentiontions in the last 12 Months or
since we started tracking (Dec 2020).
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Yazi: Fast terminal file manager written in Rust, based on async I/O
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LMAX Disruptor – High Performance Inter-Thread Messaging Library
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Kino: A high-performance Ractor web server for Ruby 4.0
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A note from our sponsor - SaaSHub
www.saashub.com | 13 Oct 2026
Index
What are some of the best open-source Concurrency projects? This list will help you:
| # | Project | Stars |
|---|---|---|
| 1 | yazi | 42,680 |
| 2 | yew | 32,819 |
| 3 | ava | 20,822 |
| 4 | Swoole | 18,921 |
| 5 | Disruptor | 18,480 |
| 6 | effect | 17,219 |
| 7 | Vert.x | 14,687 |
| 8 | rayon | 13,374 |
| 9 | Akka | 13,279 |
| 10 | moodycamel | 12,504 |
| 11 | bloc | 12,482 |
| 12 | Taskflow | 12,197 |
| 13 | ZeroMQ | 11,012 |
| 14 | Orleans | 10,896 |
| 15 | conc | 10,433 |
| 16 | actix | 9,254 |
| 17 | system_design | 9,239 |
| 18 | crossbeam | 8,599 |
| 19 | hatchet | 8,087 |
| 20 | Android-RxJava | 7,495 |
| 21 | Concurrent Ruby | 5,836 |
| 22 | promise-fun | 5,155 |
| 23 | NCCL | 5,151 |
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