Langfuse
See what your AIs are doing, and what they cost.
Langfuse traces every call from your AI applications: prompts, responses, latency, cost and quality. The essential observability tool for taking AI to production, in Europe.
- Open source souverain · Langfuse (MIT)
- ○ MCP integration in progress
- Access on request (AI Lab)
Illustrative preview, fictional data
Features
Everything you need, nothing that tracks you.
Traces
Every call, every step and every tool used by an agent, in detail.
Costs and latency
Track spending and performance by model and by user.
Prompt management
Version and deploy your prompts.
Assessments
Scores, annotations and test sets to measure quality.
Dashboards
Overview of your AI applications.
Data in Europe
Your activity stays within the Eurathos infrastructure.
Powered by Apollon
Ask, and Apollon handles it in Langfuse.
The MCP server for Langfuse is being integrated: Apollon will soon be able to act on your behalf, with your approval.
- « How much did AI calls cost this week? »
- « Show yesterday's error traces »
- « Which prompt has the best score? »
Use cases
- Understand why an agent is responding poorly.
- Manage the AI budget of an application.
- Compare two versions of a prompt.
The European alternative to
Hosted in Europe
On our servers in France, beyond the reach of the Cloud Act.
Secure single account
Eurathos sign-in with two-factor authentication and passkeys.
Open source souverain · Langfuse (MIT)
Self-hosted, updated and secured by Eurathos.
Saved
Data backed up off-site, restore tested.
Works with
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