head to head · open source
Prefect vs relay
Prefect has 24,109 GitHub stars, 2,624 forks, 858 open issues and last shipped yesterday. relay has 1,089 stars, 95 forks, 286 open issues and last shipped yesterday. Prefect leads on adoption by 2,114% (24,109 vs 1,089 stars). Prefect is written in Python under Apache-2.0; relay is written in Rust under Apache-2.0. Prefect has attracted 11% as many forks as stars, relay 9%. relay was the more recently maintained of the two, and both are self-hostable with no licence fee. The two share 1 topic tag (orchestration), 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
| Prefect | relay | |
|---|---|---|
| GitHub stars | ★ 24K | ★ 1.1K |
| License | Apache-2.0 | Apache-2.0 |
| Written in | Python | Rust |
| Last push | 2026-11-02 | 2026-11-02 |
| Forks | ⑂ 2.6K | ⑂ 95 |
| Self-hosting | Yes | Yes |
| Data ownership | Your server | Your server |
pick Prefect if
- You weight community size — 24K 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 relay if
- You want the relay feature set and don't need the biggest community
- You prefer the Apache-2.0 license terms
- Your stack matches Rust
- You evaluated both and relay fits your workflow better
About Prefect
Installation · Quickstart · Build workflows · Deploy workflows · Prefect Cloud Prefect Prefect is a workflow orchestration framework for building data pipelines in Python. It's the simplest way to elevate a script into a production workflow. With Prefect, you can build resilient, dynamic data pipelines that react to the world around them and recover from unexpected changes. With just a few lines of code, data teams can confidently automate any data process with features such as scheduling, caching, retries, and event based automations. Workflow activity is tracked and can be monitored with a self hosted Prefect…
read the full Prefect overview →
About relay
Get your agents talking. Let Claude Code message Codex. Let your Hyperagent talk to your Hermes agent. Give your custom agents a way to message each other. Relay gives all your agents shared channels, threads, DMs, reactions, files, search, and realtime events without building chat infrastructure. Quick Start Relay requires Node.js 22 or newer. Quick test with an agent Copy this snippet: Integrate with your app Install: Create quickstart.ts : Working with real Agents Agent Relay is a messaging layer but we make it very easy to work with Agents. Claude Code, Codex, and OpenCode retain PTY as their automatic…
read the full relay overview →
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Frequently asked questions
Is Prefect or relay more popular?
Prefect has 24,109 GitHub stars and relay has 1,089. Prefect has the larger community by that measure.
Are Prefect and relay free?
Both are open source. Prefect is licensed under Apache-2.0 and relay under Apache-2.0. Neither carries a licence fee.
What is the difference between Prefect and relay?
Prefect is written in Python and relay 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, Prefect or relay?
Choose Prefect if you want the larger community (24,109 stars) or its Apache-2.0 licence terms. Choose relay if its feature set, stack or Apache-2.0 licence fits better. Both are self-hostable.