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Welcome to LangChain
 Contents 
Getting Started
Modules
Use Cases
Reference Docs
Ecosystem
Additional Resources
Welcome to LangChain#
LangChain is a framework for developing applications powered by language models. We believe that the most powerful and differentiated applications will not only call out to a language model, but will also be:
Data-aware: connect a language model to other sources of data
Agentic: allow a language model to interact with its environment
The LangChain framework is designed around these principles.
This is the Python specific portion of the documentation. For a purely conceptual guide to LangChain, see here. For the JavaScript documentation, see here.
Getting Started#
How to get started using LangChain to create an Language Model application.
Quickstart Guide
Concepts and terminology.
Concepts and terminology
Tutorials created by community experts and presented on YouTube.
Tutorials
Modules#
These modules are the core abstractions which we view as the building blocks of any LLM-powered application.
For each module LangChain provides standard, extendable interfaces. LangChain also provides external integrations and even end-to-end implementations for off-the-shelf use.
The docs for each module contain quickstart examples, how-to guides, reference docs, and conceptual guides.
The modules are (from least to most complex):
Models: Supported model types and integrations.
Prompts: Prompt management, optimization, and serialization.
Memory: Memory refers to state that is persisted between calls of a chain/agent.
Indexes: Language models become much more powerful when combined with application-specific data - this module contains interfaces and integrations for loading, querying and updating external data.
Chains: Chains are structured sequences of calls (to an LLM or to a different utility).
rtdocs_stable/api.python.langchain.com/en/stable/index.html