"## Welcome to LangChain [\\#](\\#welcome-to-langchain \"Permalink to this headline\")\n",
"\n",
"**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:\n",
"\n",
"1. _Data-aware_: connect a language model to other sources of data\n",
"\n",
"2. _Agentic_: allow a language model to interact with its environment\n",
"\n",
"\n",
"The LangChain framework is designed around these principles.\n",
"\n",
"This is the Python specific portion of the documentation. For a purely conceptual guide to LangChain, see [here](https://docs.langchain.com/docs/). For the JavaScript documentation, see [here](https://js.langchain.com/docs/).\n",
"\n",
"## Getting Started [\\#](\\#getting-started \"Permalink to this headline\")\n",
"\n",
"How to get started using LangChain to create an Language Model application.\n",
"## Modules [\\#](\\#modules \"Permalink to this headline\")\n",
"\n",
"These modules are the core abstractions which we view as the building blocks of any LLM-powered application.\n",
"\n",
"For each module LangChain provides standard, extendable interfaces. LanghChain also provides external integrations and even end-to-end implementations for off-the-shelf use.\n",
"\n",
"The docs for each module contain quickstart examples, how-to guides, reference docs, and conceptual guides.\n",
"\n",
"The modules are (from least to most complex):\n",
"\n",
"- [Models](https://python.langchain.com/en/latest/modules/models.html): Supported model types and integrations.\n",
"\n",
"- [Prompts](https://python.langchain.com/en/latest/modules/prompts.html): Prompt management, optimization, and serialization.\n",
"\n",
"- [Memory](https://python.langchain.com/en/latest/modules/memory.html): Memory refers to state that is persisted between calls of a chain/agent.\n",
"\n",
"- [Indexes](https://python.langchain.com/en/latest/modules/indexes.html): 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.\n",
"\n",
"- [Chains](https://python.langchain.com/en/latest/modules/chains.html): Chains are structured sequences of calls (to an LLM or to a different utility).\n",
"\n",
"- [Agents](https://python.langchain.com/en/latest/modules/agents.html): An agent is a Chain in which an LLM, given a high-level directive and a set of tools, repeatedly decides an action, executes the action and observes the outcome until the high-level directive is complete.\n",
"\n",
"- [Callbacks](https://python.langchain.com/en/latest/modules/callbacks/getting_started.html): Callbacks let you log and stream the intermediate steps of any chain, making it easy to observe, debug, and evaluate the internals of an application.\n",
"\n",
"\n",
"## Use Cases [\\#](\\#use-cases \"Permalink to this headline\")\n",
"\n",
"Best practices and built-in implementations for common LangChain use cases:\n",
"\n",
"- [Autonomous Agents](https://python.langchain.com/en/latest/use_cases/autonomous_agents.html): Autonomous agents are long-running agents that take many steps in an attempt to accomplish an objective. Examples include AutoGPT and BabyAGI.\n",
"\n",
"- [Agent Simulations](https://python.langchain.com/en/latest/use_cases/agent_simulations.html): Putting agents in a sandbox and observing how they interact with each other and react to events can be an effective way to evaluate their long-range reasoning and planning abilities.\n",
"\n",
"- [Personal Assistants](https://python.langchain.com/en/latest/use_cases/personal_assistants.html): One of the primary LangChain use cases. Personal assistants need to take actions, remember interactions, and have knowledge about your data.\n",
"\n",
"- [Question Answering](https://python.langchain.com/en/latest/use_cases/question_answering.html): Another common LangChain use case. Answering questions over specific documents, only utilizing the information in those documents to construct an answer.\n",
"\n",
"- [Chatbots](https://python.langchain.com/en/latest/use_cases/chatbots.html): Language models love to chat, making this a very natural use of them.\n",
"\n",
"- [Querying Tabular Data](https://python.langchain.com/en/latest/use_cases/tabular.html): Recommended reading if you want to use language models to query structured data (CSVs, SQL, dataframes, etc).\n",
"\n",
"- [Code Understanding](https://python.langchain.com/en/latest/use_cases/code.html): Recommended reading if you want to use language models to analyze code.\n",
"\n",
"- [Interacting with APIs](https://python.langchain.com/en/latest/use_cases/apis.html): Enabling language models to interact with APIs is extremely powerful. It gives them access to up-to-date information and allows them to take actions.\n",
"\n",
"- [Extraction](https://python.langchain.com/en/latest/use_cases/extraction.html): Extract structured information from text.\n",
"\n",
"- [Summarization](https://python.langchain.com/en/latest/use_cases/summarization.html): Compressing longer documents. A type of Data-Augmented Generation.\n",
"\n",
"- [Evaluation](https://python.langchain.com/en/latest/use_cases/evaluation.html): Generative models are hard to evaluate with traditional metrics. One promising approach is to use language models themselves to do the evaluation.\n",
"\n",
"\n",
"## Reference Docs [\\#](\\#reference-docs \"Permalink to this headline\")\n",
"\n",
"Full documentation on all methods, classes, installation methods, and integration setups for LangChain.\n",
"## Additional Resources [\\#](\\#additional-resources \"Permalink to this headline\")\n",
"\n",
"Additional resources we think may be useful as you develop your application!\n",
"\n",
"- [LangChainHub](https://github.com/hwchase17/langchain-hub): The LangChainHub is a place to share and explore other prompts, chains, and agents.\n",
"\n",
"- [Gallery](https://python.langchain.com/en/latest/additional_resources/gallery.html): A collection of our favorite projects that use LangChain. Useful for finding inspiration or seeing how things were done in other applications.\n",
"\n",
"- [Deployments](https://python.langchain.com/en/latest/additional_resources/deployments.html): A collection of instructions, code snippets, and template repositories for deploying LangChain apps.\n",
"\n",
"- [Tracing](https://python.langchain.com/en/latest/additional_resources/tracing.html): A guide on using tracing in LangChain to visualize the execution of chains and agents.\n",
"\n",
"- [Model Laboratory](https://python.langchain.com/en/latest/additional_resources/model_laboratory.html): Experimenting with different prompts, models, and chains is a big part of developing the best possible application. The ModelLaboratory makes it easy to do so.\n",
"\n",
"- [Discord](https://discord.gg/6adMQxSpJS): Join us on our Discord to discuss all things LangChain!\n",
"\n",
"- [YouTube](https://python.langchain.com/en/latest/additional_resources/youtube.html): A collection of the LangChain tutorials and videos.\n",
"\n",
"- [Production Support](https://forms.gle/57d8AmXBYp8PP8tZA): As you move your LangChains into production, we’d love to offer more comprehensive support. Please fill out this form and we’ll set up a dedicated support Slack channel.\n"