compare
Arize Phoenix vs Langfuse
The same facts for both, read from GitHub every night, and the relation a person reviewed.
| Fact | Arize Phoenix | Langfuse |
|---|---|---|
| Language | Python | TypeScript |
| Licence | Other | Other |
| Stars | 12k | 35k |
| Latest | arize-phoenix-v20.19.0 | v4.53.0 |
| Last push | 2026-10-06 | 2026-10-06 |
| Release cadence | about 1 day between releases | about 1 day between releases |
| Active contributors | 55+ commit authors on the default branch in the last 90 days | 33+ commit authors on the default branch in the last 90 days |
| Flags | none | none |
How they relate
Both replace LangSmith. Alternatives to LangSmith →
Full replacementArize PhoenixTracing over OpenTelemetry, datasets, experiments and evaluations.
Full replacementLangfuseTracing, prompt management, datasets and evaluations, with OpenTelemetry ingestion.
Both replace W&B Weave. Alternatives to W&B Weave →
Full replacementArize PhoenixTracing and evaluations of LLM calls, built on OpenInference instrumentation.
Full replacementLangfuseTracing and evaluations of LLM calls, with SDKs for Python and JavaScript.
Arize Phoenix
- arize-phoenix-v20.19.02026-10-01arize-phoenix: v20.19.0
- @arizeai/phoenix-mcp@4.3.152026-09-30Updated dependencies [f8ae2fc]
- @arizeai/phoenix-cli@1.18.72026-09-30Updated dependencies [f8ae2fc]
- @arizeai/phoenix-client@7.16.02026-09-30f8ae2fc: Add listProjectAnnotationConfigs, assignProjectAnnotationConfig, unassignProjectAnnotationConfig, and setProje…
- arize-phoenix-v20.18.02026-09-30arize-phoenix: v20.18.0
Langfuse
- v4.53.02026-10-06feat(ai-gateway): expose resolution context in response headers, spans and logs
- v4.52.02026-10-06feat(trace-batch): bound batches by estimated weight and exclude oversized traces
- v4.51.02026-10-05feat(mcp): support decision-model evaluators
- v4.50.02026-10-02feat(web): show error id in tRPC error toast and include it in issue reports
- v4.49.02026-10-01feat(web): add org-level ingestion overview tRPC route
Arize Phoenix
✓ signed The latest release, arize-phoenix-v20.19.0, carries a signature GitHub verified.
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Langfuse
unsigned The latest release, v4.53.0, carries no signature GitHub could verify.
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