Updated March 27, 2026
Langfuse and MLflow both end up in the "tracing for LLM apps" search but they come from opposite directions and the right pick depends on what your team is actually building.
Langfuse was built for LLM applications from day one. The data model (traces, observations, sessions, prompts, evaluations) maps cleanly to how agent and RAG workloads actually run in production. Strong open-source core (MIT-licensed), self-host option, prompt management built in. The community is large and active, the integrations are LLM-shaped (LangChain, LlamaIndex, OpenAI SDK, Anthropic SDK, etc). January 2026 acquisition by ClickHouse brings strong backing.
MLflow is the classical ML platform that added LLM tracing as a feature. The strength is that if your org already runs MLflow for experiment tracking, model registry, and deployment, the LLM tracing piece slots into the same UI. The trade-off is that the LLM data model feels grafted on rather than native. Workflows that are LLM-first (agent traces, prompt management, eval pipelines) tend to feel friction-heavy compared to Langfuse.
Where the trade-off bites: Pick MLflow when your team already runs MLflow for ML workflows and you want one tool for both classical and LLM work. Pick tools like Langfuse when LLM is most of your stack and you want a platform shaped specifically for it.
Where Respan fits. Many teams pick Langfuse for the LLM-native data model but want it bundled with a gateway and evals in one platform. That is where Respan sits: same span-and-trace model as Langfuse, plus a unified LLM gateway across 1,000+ models and built-in evaluator workflows. See our Langfuse comparison article for the head-to-head.
For the operational pattern on top of either tool, RAG observability covers the 4 telemetry layers and the dashboards that matter.
Langfuse is an open-source LLM observability platform that provides tracing, analytics, prompt management, and evaluation for AI applications. It captures detailed traces of LLM calls, supports custom scoring, and integrates with LangChain, LlamaIndex, Vercel AI SDK, and raw API calls. Langfuse can be self-hosted for data privacy or used as a managed cloud service. Its open-source model and generous free tier make it popular with startups and developers.
Open-source MLOps platform with comprehensive GenAI tracing, evaluation, prompt management, and AI gateway. Maintained by the Linux Foundation.
Core capabilities each platform advertises.
What each tool does well, and the limitations to keep in mind.
Pros
Cons
Pros
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Choose Langfuse if you wantChoose if you want
Choose MLflow if you wantChoose if you want
Respan lets you trace LLM and agent calls across any model or framework, A/B test prompts on production traffic, and route requests across 1,000+ models through one gateway.
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