| Website | langfuse.com |
| Category | AI / Observability |
| License | MIT (open source) |
| Pricing | Free (self-hosted), Cloud free tier, Pro from $59/mo |
Overview
Langfuse is an open-source LLM observability platform. Trace, evaluate, and debug LLM applications. Prompt management, cost tracking, quality scoring.
Pros
- Open source (MIT)
- Trace every LLM call
- Prompt versioning and management
- Cost tracking per request
- Evaluation framework
- Integrates with LangChain, LlamaIndex
Cons
- Adds latency to LLM calls (tracing overhead)
- Self-hosting needs PostgreSQL + ClickHouse
- Dashboard can be overwhelming
- Young project, API still evolving
- Limited alerting features
Verdict
Langfuse is essential infrastructure for any team running LLM applications in production. The tracing, prompt management, and cost tracking answer the three questions every LLM team asks: what happened, which prompt version works best, and how much is this costing us. The MIT license and self-hosting option mean you keep your data.