langfuse-js

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

Packages

Package	NPM	Environments
langfuse		Node >= 18, Web, Edge
langfuse-node		Node < 18

Documentation

→ docs.langfuse.com

Development

This repository is broken into different packages

• /langfuse-core > All common code goes here.
• /langfuse-node > Node.js specific code
• /langfuse > Web/Edge/modern Node.js specific code, using fetch and browser APIs

Installing dependencies

yarn

Running tests

yarn test

Integration test

Setup

1. Start local langfuse server
2. Create testing project
3. Set environment: LF_HOST, LF_PUBLIC_KEY, LF_SECRET_KEY

Run

# Build SDKs
yarn build

# Run E2E test
yarn test:integration

Publishing a new version

Run npx lerna publish --force-publish --no-private

• Bumps version number of langfuse and langfuse-node, ignores langfuse-core
• Publishes to NPM, publishes also when there are no changes to keep the version numbers in sync
• Confirm with npmjs OTP

License

MIT

Credits

Thanks to the PostHog team for the awesome work on posthog-js-lite. This project is based on it as it was the best starting point to build a modular SDK repo to support various environments.