head to head · open source
Kestra vs haystack
Kestra has 28,146 GitHub stars, 2,997 forks, 713 open issues and last shipped yesterday. haystack has 26,531 stars, 3,144 forks, 143 open issues and last shipped yesterday. Kestra leads on adoption by 6% (28,146 vs 26,531 stars). Kestra is written in Java under Apache-2.0; haystack is written in Python under Apache-2.0. Kestra has attracted 11% as many forks as stars, haystack 12%. Kestra was the more recently maintained of the two, and both are self-hostable with no licence fee. The two share 1 topic tag (ai-agents), so they are genuine substitutes rather than adjacent tools.
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
| Kestra | haystack | |
|---|---|---|
| GitHub stars | ★ 28K | ★ 27K |
| License | Apache-2.0 | Apache-2.0 |
| Written in | Java | Python |
| Last push | 2026-09-17 | 2026-09-17 |
| Forks | ⑂ 3.0K | ⑂ 3.1K |
| Self-hosting | Yes | Yes |
| Data ownership | Your server | Your server |
pick Kestra if
- You weight community size — 28K stars and counting
- You want the Apache-2.0 license terms
- Your stack matches Java
- You value the larger contributor base for long-term maintenance
pick haystack if
- You want the haystack feature set and don't need the biggest community
- You prefer the Apache-2.0 license terms
- Your stack matches Python
- You evaluated both and haystack fits your workflow better
About Kestra
Kestra is an open source, event driven orchestration platform for data, AI, and infrastructure workflows. It operates in the Java based ecosystem and is licensed under Apache 2.0. The project provides a unified interface for both scheduled and real time automation, supporting declarative workflow definitions in YAML while also offering visual and AI assisted authoring.
read the full Kestra overview →
About haystack
Haystack is an open source AI orchestration framework written in Python under the Apache 2.0 licence, for building context engineered, production ready large language model applications as modular pipelines and agent workflows with explicit control over retrieval, routing, memory, and generation, and it is aimed at developers and teams building scalable agents, retrieval augmented generation, multimodal applications, semantic search, question answering, and conversational systems.
read the full haystack overview →
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Frequently asked questions
Is Kestra or haystack more popular?
Kestra has 28,146 GitHub stars and haystack has 26,531. Kestra has the larger community by that measure.
Are Kestra and haystack free?
Both are open source. Kestra is licensed under Apache-2.0 and haystack under Apache-2.0. Neither carries a licence fee.
What is the difference between Kestra and haystack?
Kestra is written in Java and haystack in Python. The practical differences are community size, licence terms, language stack and release cadence — all compared in the table above.
Which should I choose, Kestra or haystack?
Choose Kestra if you want the larger community (28,146 stars) or its Apache-2.0 licence terms. Choose haystack if its feature set, stack or Apache-2.0 licence fits better. Both are self-hostable.