Modular mono repo for the Langfuse JS/TS client libraries.
Important
The SDK was rewritten in v4 and released in August, 2025. Refer to the v4 migration guide for instructions on updating your code.
| Package | NPM | Description | Environments |
|---|---|---|---|
| @langfuse/client |  |
Langfuse API client for universal JavaScript environments | Universal JS |
| @langfuse/tracing |  |
Langfuse instrumentation methods based on OpenTelemetry | Node.js 20+ |
| @langfuse/otel |  |
Langfuse OpenTelemetry export helpers | Node.js 20+ |
| @langfuse/openai |  |
Langfuse integration for OpenAI SDK | Universal JS |
| @langfuse/langchain |  |
Langfuse integration for LangChain | Universal JS |
This is a monorepo managed with pnpm. See CONTRIBUTING.md for detailed development instructions.
Quick start:
pnpm install # Install dependencies
pnpm build # Build all packages
pnpm test # Run tests
pnpm ci # Run full CI suite