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Langfuse vs Arize Phoenix
Quick verdict
Langfuse and Arize Phoenix are closely matched on licensing, self-hosting and OpenTelemetry support — the decision comes down to pricing and framework integrations below.
Side-by-side comparison from the Agent Observability Index: licensing, self-hosting, pricing model and integrations — no vendor copy, primary sources linked.
| Langfuse | Arize Phoenix | |
|---|---|---|
| One-liner | Open-source (MIT) LLM engineering platform combining tracing, prompt management, evals and datasets, widely used as the default self-hosted observability stack. | Open-source, OpenTelemetry-based tracing and evaluation library that runs locally or self-hosted, serving as the OSS on-ramp to Arize's enterprise platform. |
| Category | Observability & Tracing | Observability & Tracing |
| OpenTelemetry-native | Yes | Yes |
| Open source | Yes | Yes |
| Self-hostable | Yes | Yes |
| Pricing model | freemium | free |
| Pricing notes | Free Hobby tier (50k units/mo); Core $29/mo, Pro $199/mo, unlimited users on paid tiers; MIT core fully self-hostable | Fully free OSS (Elastic License v2); hosted Phoenix Cloud has a free tier |
| Frameworks | langchain, openai-sdk, llamaindex, litellm, opentelemetry, vercel-ai, haystack | openai-sdk, langchain, llamaindex, dspy, opentelemetry, smolagents |
| GitHub stars | 29k | 10.1k |
| Maturity (GitHub signal) | 90/100 (Mature) | 90/100 (Mature) |
| Funding / ownership | YC W23; $4M seed (Lightspeed, La Famiglia) | Backed by Arize AI ($70M Series C, Feb 2025) |
How to choose
- Both link to primary pricing sources below — verify current tiers before committing; this market shifts monthly.
Sources: Langfuse · Arize Phoenix
Frequently asked questions
Is Langfuse or Arize Phoenix open source?
Langfuse: Yes. Arize Phoenix: Yes.
Can Langfuse and Arize Phoenix be self-hosted?
Langfuse: Yes. Arize Phoenix: Yes.
Langfuse vs Arize Phoenix: which should I choose?
Langfuse and Arize Phoenix are closely matched on licensing, self-hosting and OpenTelemetry support — the decision comes down to pricing and framework integrations below.