head to head · open source
haystack vs workflow-core
haystack has 26,913 GitHub stars, 3,384 forks, 143 open issues and last shipped yesterday. workflow-core has 5,939 stars, 1,261 forks, 133 open issues and last shipped 4 days ago. haystack leads on adoption by 353% (26,913 vs 5,939 stars). haystack is written in Python under Apache-2.0; workflow-core is written in C# under MIT. haystack has attracted 13% as many forks as stars, workflow-core 21%. 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.
← all 20902 open source comparisons
Side by side
| haystack | workflow-core | |
|---|---|---|
| GitHub stars | ★ 27K | ★ 5.9K |
| License | Apache-2.0 | MIT |
| Written in | Python | C# |
| Last push | 2026-11-02 | 2026-10-30 |
| Forks | ⑂ 3.4K | ⑂ 1.3K |
| 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 workflow-core if
- You want the workflow-core feature set and don't need the biggest community
- You prefer the MIT license terms
- Your stack matches C#
- You evaluated both and workflow-core 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 workflow-core
Workflow Core Workflow Core is a light weight embeddable workflow engine targeting .NET Standard. Think: long running processes with multiple tasks that need to track state. It supports pluggable persistence and concurrency providers to allow for multi node clusters. Announcements New related project: Conductor Conductor is a stand alone workflow server as opposed to a library that uses Workflow Core internally. It exposes an API that allows you to store workflow definitions, track running workflows, manage events and define custom steps and scripts for usage in your workflows. Documentation See Tutorial here…
read the full workflow-core overview →
More in Infrastructure & Operations
Related comparisons
More Orchestration & Scheduling projects
Compare either of these against the rest of the Orchestration & Scheduling field.
Frequently asked questions
Is haystack or workflow-core more popular?
haystack has 26,913 GitHub stars and workflow-core has 5,939. haystack has the larger community by that measure.
Are haystack and workflow-core free?
Both are open source. haystack is licensed under Apache-2.0 and workflow-core under MIT. Neither carries a licence fee.
What is the difference between haystack and workflow-core?
haystack is written in Python and workflow-core in C#. 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 workflow-core?
Choose haystack if you want the larger community (26,913 stars) or its Apache-2.0 licence terms. Choose workflow-core if its feature set, stack or MIT licence fits better. Both are self-hostable.