the open source movement

Replace LangSmith.

11 open source alternatives, ranked by health. We re-check every project weekly, so you don’t migrate to something abandoned.

Ranked by health

  1. LangfuseLLM engineering platform for tracing, evaluations, prompt management and metrics of LLM apps.★ 35k custom TypeScript self-host managed
  2. MLflowPlatform for tracing, evaluating and versioning LLM apps, agents and ML models, plus a prompt registry.★ 28k Apache-2.0 Python self-host managed
  3. OpikPlatform for tracing, evaluating and monitoring LLM applications, RAG systems and agents.★ 22k Apache-2.0 Python self-host managed
  4. PhoenixLLM tracing, evaluation and prompt experimentation platform built on OpenTelemetry.★ 12k Elastic License 2.0 Python self-host managed
  5. HeliconeAI gateway and LLM observability platform that logs requests, traces agent sessions and tracks cost and latency.★ 6.2k Apache-2.0 TypeScript self-host managed
  6. Coze LoopPlatform for developing, debugging, evaluating and monitoring AI agents, including prompt management and tracing.★ 5.8k Apache-2.0 Go self-host managed
  7. LangWatchPlatform for tracing, evaluating and simulation-testing LLM apps and AI agents.★ 4.9k Apache-2.0 TypeScript self-host managed
  8. LaminarObservability platform for AI agents with tracing, evaluations and analytics, self-hosted or cloud.★ 3.3k Apache-2.0 TypeScript self-host managed
  9. PezzoLLMOps platform for prompt management, versioning, delivery and request observability.★ 3.3k Apache-2.0 TypeScript self-host
  10. OpenLITOpenTelemetry-native platform for tracing, evaluating and guarding LLM apps and agents, including GPU monitoring.★ 2.8k Apache-2.0 TypeScript self-host
  11. Future AGISelf-hostable platform for tracing, evaluating, simulating and guarding LLM and agent applications.★ 2.1k Apache-2.0 Python self-host managed
How the ranking works

Health blends commit recency, release cadence, issue throughput, contributor breadth and star growth. Stars are shown but never ranked on. The full method.