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Langfuse

Open Source Agent Evals &Observability

Pricing
Freemium
Core, Pro, Enterprise

About Langfuse

Langfuse builds an open source AI engineering platform that helps teams trace, evaluate, and improve their AI agents in production. It integrates observability, prompt management, evaluations, and analytics to support the full lifecycle of AI applications. The product is designed for developers who want control over data and open standards, with self-hosting and community involvement emphasized.

Langfuse provides a single platform that combines tracing, evaluation, prompts, and experiments to understand behavior, test improvements, and ship higher quality agents. It supports production data usage and collaboration on fixes, aiming to reduce cost and latency while increasing confidence in deployments.

Langfuse advocates open standards and data portability, highlighting MIT license and OSS community engagement. It offers APIs and exports, and notes that self-hosting is possible with Docker, Kubernetes, or cloud configurations.

Langfuse presents an integration-focused approach, with features spanning observability, prompt management, evaluations, and playground-style testing. It emphasizes that all product features are MIT licensed and that the platform can scale to large volumes of observations and company deployments. The home page also notes a focus on developers and agents, with Halo and MCP tooling mentioned as part of the ecosystem.

Use cases

  • Trace every LLM call with cost and latency.
  • Manage prompts and versions across environments.
  • Run production evaluations and online/offline tests.

Key features

  • Observability: Hierarchical traces capture every LLM call and retrieval step.
  • Evaluation: LLM-as-a-judge, heuristic functions, or human review.
  • Prompt Management: Separate prompts from code with deployments and rollbacks.
  • Playground: Test prompts on real production inputs and compare models side-by-side.
  • Experiments: Define test cases and run experiments; compare results.
  • Human Annotation: Collaborative human-in-the-loop workflows to review traces.

Pros and cons

Pros

Open source MIT license and no vendor lock-in.
Integration with many frameworks and 100+ integrations.

Pricing

Core
$29/ month
  • Everything in Hobby
  • 100k units / month included
  • 90 days data access
  • Unlimited users
  • In-app support
Pro
$199/ month
  • Everything in Core
  • 100k units / month included
  • 3 years data access
  • Unlimited annotation queues
  • High rate limits
  • SOC2 & ISO27001 reports, HIPAA-ready region
Enterprise
$2499/ month
  • Everything in Pro + Teams
  • 100k units / month included
  • 3 years data access
  • Audit Logs
  • SCIM API
  • Custom rate limits
  • Uptime SLA

Reviews

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Frequently asked questions

What is Langfuse?
Langfuse is an open-source AI engineering platform that helps teams build, monitor, and improve their LLM applications. It covers the full development lifecycle with tracing, prompt management, evaluations, and analytics dashboards — all in one place.
What deployment options exist?
Langfuse can be self-hosted using Docker on your own infrastructure; deployment options include Kubernetes, AWS, Azure, GCP, Render, or Railway in community contexts.

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