InfrastructureOpen source

Langfuse

Open-source LLM engineering platform: tracing, evals, prompt management, and datasets. Self-hostable, OpenTelemetry-native, with 50+ framework integrations.

Try Langfuselangfuse.com

Save

Langfuse is the open-source platform for seeing what your LLM application actually did. Its tracing captures every model call, retrieval step, and agent action across multi-turn conversations and complex agent workflows, while prompt management adds versioning, deployment, and a built-in playground, and the evaluation layer supports LLM-as-judge, code evaluators, user feedback, and manual review. It is OpenTelemetry-native to reduce vendor lock-in and integrates with the OpenAI SDK, LangChain, LlamaIndex, LiteLLM, and 50+ other libraries via Python and JavaScript SDKs. You can self-host the full stack or use their cloud. Once an agent system grows past a prototype, this is the observability layer that makes debugging it tractable.

infrastructure observability llm tracing evals open-source self-hosted

Langfuse at a glance

Last verified October 17, 2026

Pricing: Self-hosted Open Source - free under the MIT license, except the ee folders
Self-hosted Enterprise - custom pricing
Cloud Hobby - free: 50k units/mo, 30 days data access, 2 users
Cloud Core - $29/mo: 100k units/mo included, then $8 per 100k units, 90 days data access, unlimited users
Cloud Pro - $199/mo: 100k units/mo included, then $8 per 100k units, 3 years data access, unlimited users
Cloud Enterprise - $2499/mo: 100k units/mo included, then $8 per 100k units, 3 years data access, unlimited users
Install: pip install langfuse openai
npm install @langfuse/client@6 @langfuse/tracing@6 @langfuse/otel@6
git clone --depth=1 https://github.com/langfuse/langfuse.git && cd langfuse && docker compose up
Models: Langfuse works with any model. It traces calls through OpenTelemetry and its Python and JS/TS SDKs, with integrations for the OpenAI SDK, LangChain, LlamaIndex, LiteLLM and others. LLM-as-a-judge evaluators run on LLM connections you configure, which can be set once per organization and overridden per project.
Recent changes: Oct 16Project API keys can be created with scoped permissions: Full access, Viewer, Ingestion, or Scores ingestion.
Oct 14Python SDK v5 and JS/TS SDK v6 ship for Langfuse v4, with experiment links, typed metadata filters, and compressed span export.
Aug 17Langfuse v4 replaces read-time joins with a denormalized observations table. Initial table loads now take milliseconds and dashboards are at least 10x faster. It also adds monitors, code evaluators, full-text search and the Halo plain-language query tool.

Sources: Langfuse Cloud pricing, Self-hosted pricing, langfuse/langfuse README, Langfuse changelog, Python SDK v5 and JS/TS SDK v6, Langfuse v4, Project API key permissions

Similar Tools

Infrastructure

Coolify

Self-hosted PaaS for deploying apps, databases, and services. Git-based deploys, Docker support, preview environments, and a clean UI.

Infrastructure

Supabase

Open-source Firebase alternative built on Postgres. Auth, real-time subscriptions, storage, edge functions, and pgvector for AI embeddings. Generous free tier.

Infrastructure

E2B

Open-source cloud sandboxes that run each AI agent session in its own microVM. Isolated environments that start in under 200ms, run code in Python, JavaScript, and more, and persist sessions up to 24 hours.

Infrastructure

Vercel

Deployment platform behind Next.js. Git push to deploy. Edge functions, image optimization, analytics. Free tier is generous.

Get started with Langfuse

Open-source LLM engineering platform: tracing, evals, prompt management, and datasets. Self-hostable, OpenTelemetry-native, with 50+ framework integrations.

Try Langfuse

Get weekly tool reviews

Honest takes on AI dev tools, frameworks, and infrastructure - delivered to your inbox.

Subscribe Free

Compare all pricing Compare side by side

More Infrastructure Tools

Vercel

Deployment platform behind Next.js. Git push to deploy. Edge functions, image optimization, analytics. Free tier is generous.

Coolify

Self-hosted PaaS for deploying apps, databases, and services. Git-based deploys, Docker support, preview environments, and a clean UI.

Convex

Reactive backend - database, server functions, real-time sync, cron jobs, file storage. All TypeScript. This site's backend (courses, videos, user data) runs on Convex.