A complete set of interoperable building blocks
Build end-to-end applications with an extensive library of components. Want to change your model? Future-proof your application by incorporating vendor optionality into your LLM infrastructure design.
LangChain’s flexible abstractions and AI-first toolkit make it the #1 choice for developers when building with GenAI.
Join 1M+ builders standardizing their LLM app development
in LangChain's Python and JavaScript frameworks.
Build end-to-end applications with an extensive library of components. Want to change your model? Future-proof your application by incorporating vendor optionality into your LLM infrastructure design.
Create a composable app fit for your needs with LangChain Expression Language (LCEL). Get out-of-the-box support for parallelization, fallbacks, batch, streaming, and async methods, freeing you to focus on what matters.
LangChain connects LLMs to your company’s private data and APIs to build context-aware, reasoning applications. Rapidly move from prototype to production with popular methods like RAG or simple chains.
LangSmith shines a light into application behavior and performance. Get prompt-level visibility coupled with tools to debug, test, evaluate, deploy, and monitor your applications with your team.
Yes - LangChain is valuable even if you’re using one provider. Its LangChain Expression Language standardizes methods such as parallelization, fallbacks, and async for more durable execution. We also provide observability out of the box with LangSmith, making the process of getting to production more seamless.
Yes - LangChain is an MIT-licensed open-source library and is free to use.
LangChain is often used for chaining together a series of LLM calls or for retrieval augmented generation. We recommend you try out LangGraph if you want to build an agent.
Yes, LangChain 0.1 and later are production-ready. We've streamlined the package, which has fewer dependencies for better compatibility with the rest of your code base. We're also committed to no breaking changes on any minor version of LangChain after 0.1, so you can upgrade your patch versions (e.g., 0.2.x) on any minor version without impact.
Yes, LangChain is widely used by Fortune 2000 companies. Many enterprises use LangChain to future-proof their stack, allowing for the easy integration of additional model providers as their needs evolve. Visit our to see how companies are using LangChain.
For straight-forward chains and retrieval flows, start building with LangChain using LangChain Expression Language to piece together components. If you’re building agents or need complex orchestration, use LangGraph instead.
Start by hosting a meetup, building a digital community, or creating educational content - and share it with us in our Community Slack!