Langfuse JS/TS

[!IMPORTANT] This SDK is deprecated. The Langfuse TypeScript SDK was completely rewritten and released as v4 in August 2025. Please refer to the TypeScript SDK documentation for migration instructions.

This is the main JS/TS client for Langfuse.

Documentation

• Docs: https://langfuse.com/docs/sdk/typescript
• Reference: https://js.reference.langfuse.com/modules/langfuse.html

Environments

Supported

• Node.js >=18
• Web
• Edge: Vercel, Cloudflare Workers, etc.

Using Node.js <18? Use langfuse-node instead as it does not use fetch and other Web APIs

Installation

npm i langfuse
# or
yarn add langfuse
# or
pnpm i langfuse