Agentic Index
Fiddler Ai vs Langfuse (2026)
Both score 7.5 of 14 watching AI in production and they sell to different buyers.
Langfuse is engineering first: open source tracing, prompt management and evaluation, self hostable, free for 50,000 units monthly then 29 dollars. Fiddler is an enterprise observability and security control plane spanning agents, LLM applications and machine learning models, with real time guardrails, explainability and governance, quoted through sales across three tiers. Langfuse is what your engineers will adopt this afternoon; Fiddler is what your risk function will ask for when the models start making decisions that matter.
Choose Fiddler Ai if
- Explainability and governance are requirements from your risk function, not your engineers.
- Traditional machine learning models alongside agents and LLM applications are in scope.
- Real time guardrails are a control you need in the path, not a dashboard.
Choose Langfuse if
- Open source and self hostable is a requirement.
- Twenty nine dollars a month with a real free tier means adoption needs no approval.
- Prompt management alongside tracing is the combination your engineers want.
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