Arize Phoenix vs Langfuse vs LangWatch vs OpenLLMetry
A side-by-side look at scores, pricing and features — with RECATOOLS' ASEAN-aware verdict for each.
Arize Phoenix
Open-source LLM evaluation and observability
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Langfuse
Open-source LLM observability and analytics
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LangWatch
OpenTelemetry-native LLMOps platform for tracing, evals and agents
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OpenLLMetry
OpenTelemetry-based LLM observability
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| RECATOOLS Score | 7.8 / 10 | 8.4 / 10 | 7.5 / 10 | 7 / 10 |
| Capability | ||||
| Value for money | ||||
| Ease of use | ||||
| ASEAN readiness | ||||
| API quality | ||||
| Pricing | Open Source | Open Source | Freemium | Open Source |
| Free tier | — | — | — | — |
| Paid from | — | — | — | — |
| Has API | ✓ | ✓ | ✓ | ✓ |
| Open source | ✓ | ✓ | ✓ | ✓ |
| Free to use | ✓ | ✓ | ✓ | ✓ |
| Users | — | — | — | — |
| Founded | 2023 | 2023 | — | 2023 |
| Maker | — | — | — | — |
| Verdict | Arize Phoenix is an open-source observability and evaluation toolkit for LLM and AI applications, offering tracing, prompt and RAG debugging, evals, and OpenTelemetry-based instrumentation that runs locally or self-hoste... |
Langfuse is a leading open-source LLM observability platform covering tracing, prompt management, evaluations, cost tracking and analytics, with framework-agnostic SDKs that work well alongside LangChain, LlamaIndex or r... |
LangWatch's most interesting move isn't a feature, it's the pricing shift it made in February 2026: away from per-trace billing (the model Langfuse and LangSmith both use, which can spike hard as usage grows) toward seat... |
OpenLLMetry by Traceloop is an open-source observability layer for LLM applications built on OpenTelemetry standards, auto-instrumenting popular frameworks (LangChain, LlamaIndex, OpenAI, etc.) to trace prompts, completi... |
| Full review → | Full review → | Full review → | Full review → |
Comparisons cover up to 4 tools. Scores are RECATOOLS editorial assessments; verify current pricing on each vendor's site.