https://github.com/langfuse/langfuse-js

🪢 Langfuse JS/TS SDKs - Instrument your LLM app and get detailed tracing/observability. Works with any LLM or framework
https://github.com/langfuse/langfuse-js

javascript langfuse llmops observability sdk-js typescript

Last synced: 5 days ago
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🪢 Langfuse JS/TS SDKs - Instrument your LLM app and get detailed tracing/observability. Works with any LLM or framework

• Host: GitHub
• URL: https://github.com/langfuse/langfuse-js
• Owner: langfuse
• License: other
• Created: 2023-07-02T21:43:44.000Z (almost 3 years ago)
• Default Branch: main
• Last Pushed: 2026-05-20T09:38:03.000Z (15 days ago)
• Last Synced: 2026-05-20T13:20:22.701Z (15 days ago)
• Topics: javascript, langfuse, llmops, observability, sdk-js, typescript
• Language: TypeScript
• Homepage: https://langfuse.com/docs/sdk/typescript
• Size: 5.66 MB
• Stars: 140
• Watchers: 2
• Forks: 86
• Open Issues: 19
• Metadata Files:
  • Readme: README.md
  • Changelog: CHANGELOG.md
  • Contributing: CONTRIBUTING.md
  • License: LICENSE
  • Codeowners: .github/CODEOWNERS
  • Agents: AGENTS.md

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README

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

# langfuse-js

[![MIT License](https://img.shields.io/badge/License-MIT-red.svg?style=flat-square)](https://opensource.org/licenses/MIT)

[![CI test status](https://img.shields.io/github/actions/workflow/status/langfuse/langfuse-js/ci.yml?style=flat-square&label=All%20tests)](https://github.com/langfuse/langfuse-js/actions/workflows/ci.yml?query=branch%3Amain)

[![GitHub Repo stars](https://img.shields.io/github/stars/langfuse/langfuse?style=flat-square&logo=GitHub&label=langfuse%2Flangfuse)](https://github.com/langfuse/langfuse)

[![Discord](https://img.shields.io/discord/1111061815649124414?style=flat-square&logo=Discord&logoColor=white&label=Discord&color=%23434EE4)](https://discord.gg/7NXusRtqYU)

[![YC W23](https://img.shields.io/badge/Y%20Combinator-W23-orange?style=flat-square)](https://www.ycombinator.com/companies/langfuse)

Modular mono repo for the Langfuse JS/TS client libraries.

## Packages

> [!IMPORTANT]

> The SDK was rewritten in v5 and released in March 2026. Refer to the [v5 migration guide](https://langfuse.com/docs/observability/sdk/upgrade-path/js-v4-to-v5) for instructions on updating your code.

| Package                                     | NPM                                                                                                               | Description                                               | Environments |

| ------------------------------------------- | ----------------------------------------------------------------------------------------------------------------- | --------------------------------------------------------- | ------------ |

| [@langfuse/client](./packages/client)       | [![NPM](https://img.shields.io/npm/v/@langfuse/client.svg)](https://www.npmjs.com/package/@langfuse/client)       | Langfuse API client for universal JavaScript environments | Universal JS |

| [@langfuse/tracing](./packages/tracing)     | [![NPM](https://img.shields.io/npm/v/@langfuse/tracing.svg)](https://www.npmjs.com/package/@langfuse/tracing)     | Langfuse instrumentation methods based on OpenTelemetry   | Node.js 20+  |

| [@langfuse/otel](./packages/otel)           | [![NPM](https://img.shields.io/npm/v/@langfuse/otel.svg)](https://www.npmjs.com/package/@langfuse/otel)           | Langfuse OpenTelemetry export helpers                     | Node.js 20+  |

| [@langfuse/openai](./packages/openai)       | [![NPM](https://img.shields.io/npm/v/@langfuse/openai.svg)](https://www.npmjs.com/package/@langfuse/openai)       | Langfuse integration for OpenAI SDK                       | Universal JS |

| [@langfuse/langchain](./packages/langchain) | [![NPM](https://img.shields.io/npm/v/@langfuse/langchain.svg)](https://www.npmjs.com/package/@langfuse/langchain) | Langfuse integration for LangChain                        | Universal JS |

## Documentation

- [Docs](https://langfuse-docs-git-add-js-sdk-v4-docs-langfuse.vercel.app/docs/observability/sdk/typescript/overview)

- [Reference](https://langfuse-js-git-main-langfuse.vercel.app/)

## Development

This is a monorepo managed with pnpm. See [CONTRIBUTING.md](./CONTRIBUTING.md) for detailed development instructions.

Quick start:

```bash

pnpm install    # Install dependencies

pnpm build      # Build all packages

pnpm test       # Run tests

pnpm ci         # Run full CI suite

```

## License

[MIT](LICENSE)