head to head · open source
haystack vs moon
haystack has 26,913 GitHub stars, 3,384 forks, 143 open issues and last shipped yesterday. moon has 4,175 stars, 260 forks, 99 open issues and last shipped yesterday. haystack leads on adoption by 545% (26,913 vs 4,175 stars). haystack is written in Python under Apache-2.0; moon is written in Rust under MIT. haystack has attracted 13% as many forks as stars, moon 6%. haystack was the more recently maintained of the two, and both are self-hostable with no licence fee.
Two open source projects, one decision. Both are free and self-hostable — the differences are community size, license terms, language stack and release pace.
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Side by side
| haystack | moon | |
|---|---|---|
| GitHub stars | ★ 27K | ★ 4.2K |
| License | Apache-2.0 | MIT |
| Written in | Python | Rust |
| Last push | 2026-11-02 | 2026-11-02 |
| Forks | ⑂ 3.4K | ⑂ 260 |
| Self-hosting | Yes | Yes |
| Data ownership | Your server | Your server |
pick haystack if
- You weight community size — 27K stars and counting
- You want the Apache-2.0 license terms
- Your stack matches Python
- You value the larger contributor base for long-term maintenance
pick moon if
- You want the moon feature set and don't need the biggest community
- You prefer the MIT license terms
- Your stack matches Rust
- You evaluated both and moon fits your workflow better
About haystack
🎉🎊✨ Haystack 3.0 is out! ✨🎊🎉 Read the announcement here! 🥳 🎈 🎆 🪅 🎇 🍾 🥂 🎁 🌈 Haystack is an open source AI orchestration framework for building production ready LLM applications in Python. Design modular pipelines and agent workflows with explicit control over retrieval, routing, memory, and generation. Build scalable RAG systems, multimodal applications, semantic search, question answering, and autonomous agents, all in a transparent architecture that lets you experiment, customize deeply, and deploy with confidence. Table of Contents Installation Documentation Features Haystack Enterprise: Support &…
read the full haystack overview →
About moon
moon moon is a repository m anagement, o rganization, o rchestration, and n otification tool for the web ecosystem, written in Rust. Many of the concepts within moon are heavily inspired from Bazel and other popular build systems. Documentation Contributing Code of conduct Why use moon? Working in a developer ecosystem can be very involved, especially when it comes to managing a repository effectively. Which package manager to use? Which language version to use? How to import packages? How to build code? So on and so forth. moon aims to streamline this entire process and provide a first class developer…
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Frequently asked questions
Is haystack or moon more popular?
haystack has 26,913 GitHub stars and moon has 4,175. haystack has the larger community by that measure.
Are haystack and moon free?
Both are open source. haystack is licensed under Apache-2.0 and moon under MIT. Neither carries a licence fee.
What is the difference between haystack and moon?
haystack is written in Python and moon in Rust. The practical differences are community size, licence terms, language stack and release cadence — all compared in the table above.
Which should I choose, haystack or moon?
Choose haystack if you want the larger community (26,913 stars) or its Apache-2.0 licence terms. Choose moon if its feature set, stack or MIT licence fits better. Both are self-hostable.