langchain-ai/langchainjs

Provides standardized abstractions for chaining LLMs with agents, embeddings, vector stores, and 100+ third-party integrations for real-time data augmentation. Built in TypeScript with modular components enabling model swapping and rapid iteration across Node.js, browsers, Cloudflare Workers, and edge runtimes. Integrates with LangGraph for advanced agent orchestration and LangSmith for production monitoring, evaluation, and debugging.

17,310 stars and 1,027,441 monthly downloads. Used by 2 other packages. Actively maintained with 200 commits in the last 30 days. Available on npm.