LangChain.js
the six Ws · specification
JavaScript and TypeScript developers building chatbots, agents, or retrieval apps for Node or the browser.
The official JavaScript and TypeScript port of LangChain, providing chains, agents, memory, and retrieval building blocks for LLM applications.
Runs in Node.js, edge runtimes like Vercel and Cloudflare Workers, and browser environments.
Use when a JavaScript stack needs the same orchestration primitives that LangChain provides in Python.
It lets JS-first teams compose LLM calls, tools, and retrieval without reimplementing orchestration logic.
Integrates with most LLM providers, vector stores, and the broader LangChain and LangGraph ecosystem.
Open source, MIT licensed, maintained by LangChain Inc; free core with optional paid LangSmith integration.
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