langchainjs

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  <h3>The agent engineering platform.</h3>
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![npm](https://img.shields.io/npm/dm/langchain) [![License: MIT](https://img.shields.io/badge/License-MIT-yellow.svg)](https://opensource.org/licenses/MIT) [![Twitter](https://img.shields.io/twitter/url/https/twitter.com/langchain_js.svg?style=social&label=Follow%20%40LangChain)](https://x.com/langchain_js)

LangChain is a framework for building LLM-powered applications. It helps you chain together interoperable components and third-party integrations to simplify AI application development — all while future-proofing decisions as the underlying technology evolves.

> [!TIP]
> Just getting started? Check out **[Deep Agents](http://docs.langchain.com/oss/javascript/deepagents/)** — a higher-level package built on LangChain for agents that have built-in capabilities for common usage patterns such as planning, subagents, file system usage, and more.

**Documentation**: To learn more about LangChain, check out [the docs](https://docs.langchain.com/oss/javascript/langchain/overview).

If you're looking for more advanced customization or agent orchestration, check out [LangGraph.js](https://docs.langchain.com/oss/javascript/langgraph/overview), our framework for building agents and controllable workflows.

For an equivalent Python library, check out [LangChain](https://github.com/langchain-ai/langchain).

To help you ship LangChain apps to production faster, check out [LangSmith](https://smith.langchain.com), a unified developer platform for building, testing, and monitoring LLM applications.

## ⚡️ Quick Install

You can use npm, pnpm, or yarn to install LangChain.js

`npm install -S langchain` or `pnpm install langchain` or `yarn add langchain`

## 🚀 Why use LangChain?

LangChain helps developers build applications powered by LLMs through a standard interface for agents, models, embeddings, vector stores, and more.

Use LangChain for:

- **Real-time data augmentation**. Easily connect LLMs to diverse data sources and external/internal systems, drawing from LangChain’s vast library of integrations with model providers, tools, vector stores, retrievers, and more.
- **Model interoperability**. Swap models in and out as your engineering team experiments to find the best choice for your application’s needs. As the industry frontier evolves, adapt quickly — LangChain’s abstractions keep you moving without losing momentum.
- **Rapid prototyping**. Quickly build and iterate on LLM applications with LangChain's modular, component-based architecture. Test different approaches and workflows without rebuilding from scratch, accelera