head to head · open source
haystack vs nextflow
haystack has 26,531 GitHub stars, 3,144 forks, 143 open issues and last shipped yesterday. nextflow has 3,487 stars, 811 forks, 422 open issues and last shipped yesterday. haystack leads on adoption by 661% (26,531 vs 3,487 stars). haystack is written in Python under Apache-2.0; nextflow is written in Groovy under Apache-2.0. haystack has attracted 12% as many forks as stars, nextflow 23%. nextflow 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 | nextflow | |
|---|---|---|
| GitHub stars | ★ 27K | ★ 3.5K |
| License | Apache-2.0 | Apache-2.0 |
| Written in | Python | Groovy |
| Last push | 2026-09-17 | 2026-09-17 |
| Forks | ⑂ 3.1K | ⑂ 811 |
| 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 nextflow if
- You want the nextflow feature set and don't need the biggest community
- You prefer the Apache-2.0 license terms
- Your stack matches Groovy
- You evaluated both and nextflow fits your workflow better
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 →
About nextflow
Nextflow is an open source workflow system for scalable, portable, and reproducible computational pipelines. It is written in Groovy, released under Apache 2.0, and built around a domain specific language for data driven workflows. The project lives in the infrastructure and operations ecosystem, especially orchestration and scheduling, and its topics include bioinformatics, cloud, Docker, high performance computing, and reproducible research.
read the full nextflow overview →
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Frequently asked questions
Is haystack or nextflow more popular?
haystack has 26,531 GitHub stars and nextflow has 3,487. haystack has the larger community by that measure.
Are haystack and nextflow free?
Both are open source. haystack is licensed under Apache-2.0 and nextflow under Apache-2.0. Neither carries a licence fee.
What is the difference between haystack and nextflow?
haystack is written in Python and nextflow in Groovy. 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 nextflow?
Choose haystack if you want the larger community (26,531 stars) or its Apache-2.0 licence terms. Choose nextflow if its feature set, stack or Apache-2.0 licence fits better. Both are self-hostable.