Langfuse
hybridFree (self-hosted)Free cloud (50k observations)$59/mo ProCustom Enterpriseopen source
Best for
Open-source LLM tracing, prompt management, and evaluation — self-hostable with broad framework support
Limitations
Smaller ecosystem than Datadog; self-hosted requires Postgres + ClickHouse; evaluation features are still maturing
Features
Llm Tracing
Trace LLM calls, tool invocations, and agent reasoning steps end-to-end
Cost Tracking
Track token usage and cost per request, per agent run, and per model
Evaluation
Score agent outputs against test datasets with automated evaluators
Prompt Management
Version, manage, and A/B test prompts in production
Real Time Monitoring
Live dashboards and alerting for agent performance metrics
Frameworks
langchainllamaindexvercel-aiopenai-agents
SDK Languages
pythonjavascripttypescript
Compliance
soc2gdpr
Langfuse
Langfuse is an open-source observability platform built specifically for LLM applications. It provides tracing, prompt management, evaluation, and dataset curation — all focused on the AI agent development lifecycle.
Its decorator-based Python SDK and JS integration make it straightforward to add tracing to LangChain, LlamaIndex, Vercel AI, and OpenAI agent workflows. The self-hosted option (MIT license) is a major differentiator for teams with data residency requirements.
Last verified: 2026-04-28Verified by: editorial