Compare / Langfuse vs Phoenix
Langfuse vs Phoenix
Pick Langfuse if you want MIT-core traces and evals (the published LangSmith stack — skip ee/). Pick Phoenix only if you accept Elastic License 2.0 — not OSI; you may not offer it as a hosted service to third parties.
Facts checked 21 Oct 2026. License, language, and GitHub activity come from the catalog or the project's own repo. "Not in the catalog row" means the public catalog dump does not store that number.
Langfuse in the catalog Phoenix in the catalog Start on Railway
How they compare
| Langfuse | Phoenix | |
|---|---|---|
| License | MIT core (catalog; skip ee/) source | Elastic License 2.0 (catalog) — not OSI source |
| Language | TypeScript (catalog) | Python (catalog) |
| GitHub activity | 36,145 stars in the catalog source | 11,939 stars in the catalog source |
| Self-host | Published as /stacks/langfuse-observe. Postgres. Skip ee/. | Self-host allowed. ELv2 forbids offering it as a hosted service to third parties. |
| Best for | The published LangSmith replacement. | ELv2 evals if you accept that license. |
Self-hosting and resource needs
Langfuse is on /stacks/langfuse-observe. Phoenix is Arize-ai/phoenix. Helicone is the Apache-2.0 proxy — /compare/langfuse-vs-helicone. Training runs stay on /replace/wandb. Do not call Phoenix the OSS path.
FAQ
- Is Phoenix open source?
- Not OSI. Elastic License 2.0. Langfuse core is MIT if you skip ee/.
- Langfuse or Helicone?
- /compare/langfuse-vs-helicone.
- Are these free?
- Langfuse core is MIT. Phoenix is ELv2. You pay hosting and model tokens.
- How do I deploy Langfuse?
- Open /stacks/langfuse-observe. Persist Postgres. Point one app at the ingest URL.
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