![GitHub Banner](https://github.com/langfuse/langfuse-js/assets/2834609/d1613347-445f-4e91-9e84-428fda9c3659)

# Langfuse Core

[![npm package](https://img.shields.io/npm/v/langfuse-core?style=flat-square)](https://www.npmjs.com/package/langfuse-core)

> [!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](https://langfuse.com/docs/observability/sdk/typescript/overview) for migration instructions.

This is the core package for the Langfuse JS/TS client libraries. It is not meant to be used directly.

Reference: https://js.reference.langfuse.com/modules/langfuse_core.html

**Client Libraries**

| Package                                                                                    | NPM                                                                                                                                   | Environments          |
| ------------------------------------------------------------------------------------------ | ------------------------------------------------------------------------------------------------------------------------------------- | --------------------- |
| [langfuse](https://github.com/langfuse/langfuse-js/tree/main/langfuse)                     | [![npm package](https://img.shields.io/npm/v/langfuse?style=flat-square)](https://www.npmjs.com/package/langfuse)                     | Node >= 18, Web, Edge |
| [langfuse-node](https://github.com/langfuse/langfuse-js/tree/main/langfuse-node)           | [![npm package](https://img.shields.io/npm/v/langfuse-node?style=flat-square)](https://www.npmjs.com/package/langfuse-node)           | Node < 18             |
| [langfuse-langchain](https://github.com/langfuse/langfuse-js/tree/main/langfuse-langchain) | [![npm package](https://img.shields.io/npm/v/langfuse-langchain?style=flat-square)](https://www.npmjs.com/package/langfuse-langchain) | Node >= 20, Web, Edge |
