Replace / Weights and Biases
Best free Weights and Biases alternatives (open source, self-hosted) 2026
The best open-source alternative to Weights and Biases is MLflow or Aim, self-hosted on Railway. Experiment tracking you host. MLflow is Apache-2.0; Aim is Apache-2.0 — Weights and Biases without the hosted run meter.
Estimated save $1,200 a year.
Open the stackStart on Railway
How Weights and Biases compares
| Weights and Biases | MLflow / Aim | |
|---|---|---|
| Pricing model | Hosted subscription | Open-source or fair-code license; you pay the host |
| Hosting | Vendor cloud | Self-hosted on Railway or any VPS |
| Rough monthly cost | Public list price not verified this run | Hosting only — no SaaS seat meter in this repo |
- MLflow
Apache-2.0 experiment tracking, models, and evaluation
- Aim
Apache-2.0 experiment tracker if MLflow is not the shape
FAQ
- What is the best free open-source Weights and Biases alternative?
- The best open-source alternative to Weights and Biases is MLflow or Aim, self-hosted on Railway. Experiment tracking you host. MLflow is Apache-2.0; Aim is Apache-2.0 — Weights and Biases without the hosted run meter.
- Is it free?
- The MLflow / Aim licenses are open source or fair-code. You still pay hosting (Railway or any VPS) and any APIs the stack calls. There is no Weights and Biases seat or task bill on this path.
- Can I migrate from Weights and Biases?
- Yes. Start with the workflows or data you actually use, then cut over. The MLflow / Aim stack page has the agent prompt and the cost table; most teams rebuild the slice that matters and leave old Weights and Biases links until they expire.
- How do I deploy it?
- Open the MLflow / Aim stack, copy the agent prompt, and deploy on Railway (one service, PORT, and a volume when the app needs disk). Placeholder: MLflow tracking server plus a volume or S3-compatible store for artifacts. Aim if you want that UI. No one-click template in this repo yet — Start on Railway. LLM traces stay on /stacks/langfuse-observe.
- What does this replace?
- Weights and Biases. The published small-team estimate on this stack is $1,200 a year.
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