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Langfuse: the best Open Source alternative to Datadog LLM Observability in 2026

Langfuse is an open source observability and evaluation platform for LLM applications: traces, per-request costs, evaluation datasets and prompt management, self-hostable alongside your AI stack.

License MIT 33.9k stars liveUpdated hoyWebsite GitHub Repository

Technical profile

License
MIT
Category
Artificial Intelligence
Replaces
Datadog LLM Observability
Tech stack
TypeScriptNext.jsPostgreSQLClickHouse

Preview

Langfuse interface preview

Public image provided by Langfuse on its own website.

Key features

  • Detailed traces for every LLM call
  • Prompt management with versioning
  • Datasets and automatic evaluations

Langfuse vs. Datadog LLM Observability

Pros

  • MIT core, with optional separate enterprise features

Things to consider

  • Large-scale deployment adds ClickHouse and Redis

Quick Docker installation guide

Copy this docker-compose.yml, adjust the example passwords and run docker compose up -d on your server. See the full step-by-step guide →

docker-compose.yml
version: "3.9"
services:
  langfuse:
    image: langfuse/langfuse:latest
    restart: unless-stopped
    ports:
      - "3000:3000"
    environment:
      - DATABASE_URL=postgresql://langfuse:langfuse@langfuse-db:5432/langfuse
      - NEXTAUTH_SECRET=change-me-super-secret
      - SALT=change-me-salt
    depends_on:
      - langfuse-db
  langfuse-db:
    image: postgres:15-alpine
    restart: unless-stopped
    environment:
      - POSTGRES_USER=langfuse
      - POSTGRES_PASSWORD=langfuse
      - POSTGRES_DB=langfuse
    volumes:
      - langfuse_pg_data:/var/lib/postgresql/data
volumes:
  langfuse_pg_data: