head to head · open source
haystack vs nextflow
haystack has 26,913 GitHub stars, 3,384 forks, 143 open issues and last shipped yesterday. nextflow has 3,520 stars, 820 forks, 422 open issues and last shipped yesterday. haystack leads on adoption by 665% (26,913 vs 3,520 stars). haystack is written in Python under Apache-2.0; nextflow is written in Groovy under Apache-2.0. haystack has attracted 13% 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 | 2026-11-02 | 2026-11-02 |
| Forks | ⑂ 3.4K | ⑂ 820 |
| 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 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 nextflow
"Dataflow variables are spectacularly expressive in concurrent programming" Henri E. Bal , Jennifer G. Steiner , Andrew S. Tanenbaum Nextflow is a workflow system for creating scalable, portable, and reproducible workflows. It is based on the dataflow programming model, which greatly simplifies the writing of parallel and distributed pipelines, allowing you to focus on the flow of data and computation. Nextflow can deploy workflows on a variety of execution platforms, including your local machine, HPC schedulers, AWS Batch, Azure Batch, Google Cloud Batch, and Kubernetes. Additionally, it supports many ways to…
read the full nextflow overview →
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Frequently asked questions
Is haystack or nextflow more popular?
haystack has 26,913 GitHub stars and nextflow has 3,520. 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 (26,913 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.