[,bash]
----
pip install langchain
# or
uv add langchain
----

[,python]
----
from langchain.chat_models import init_chat_model

model = init_chat_model("openai:gpt-5.4")
result = model.invoke("Hello, world!")
----

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

> [!TIP]
> For developing, debugging, and deploying AI agents and LLM applications, see https://docs.langchain.com/langsmith/home[LangSmith].

While the LangChain framework can be used standalone, it also integrates seamlessly with any LangChain product, giving developers a full suite of tools when building LLM applications.

* *https://github.com/langchain-ai/deepagents[Deep Agents]* -- Build agents that can plan, use subagents, and leverage file systems for complex tasks
* *https://docs.langchain.com/oss/python/langgraph/overview[LangGraph]* -- Build agents that can reliably handle complex tasks with our low-level agent orchestration framework
* *https://docs.langchain.com/oss/python/integrations/providers/overview[Integrations]* -- Chat & embedding models, tools & toolkits, and more
* *https://www.langchain.com/langsmith[LangSmith]* -- Agent evals, observability, and debugging for LLM apps
* *https://docs.langchain.com/langsmith/deployments[LangSmith Deployment]* -- Deploy and scale agents with a purpose-built platform for long-running, stateful workflows

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

* *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, accelerating your development cycle
* *Production-ready features* -- Deploy reliable applications with built-in support for monitoring, evaluation, and debugging through integrations like LangSmith. Scale with confidence using battle-tested patterns and best practices
* *Vibrant community and ecosystem* -- Leverage a rich ecosystem of integrations, templates, and community-contributed components. Benefit from continuous improvements and stay up-to-date with the latest AI developments through an active open-source community
* *Flexible abstraction layers* -- Work at the level of abstraction that suits your needs -- from high-level chains for quick starts to low-level components for fine-grained control. LangChain grows with your application's complexity

'''

* https://docs.langchain.com/oss/python/langchain/overview[docs.langchain.com] -- Comprehensive documentation, including conceptual overviews and guides
* https://reference.langchain.com/python[reference.langchain.com/python] -- API reference docs for LangChain packages
* https://chat.langchain.com/[Chat LangChain] -- Chat with the LangChain documentation and get answers to your questions

*Discussions*: Visit the https://forum.langchain.com[LangChain Forum] to connect with the community and share all of your technical questions, ideas, and feedback.

* https://docs.langchain.com/oss/python/contributing/overview[Contributing Guide] -- Learn how to contribute to LangChain projects and find good first issues.
* https://github.com/langchain-ai/langchain/?tab=coc-ov-file[Code of Conduct] -- Our community guidelines and standards for participation.
* https://academy.langchain.com/[LangChain Academy] -- Comprehensive, free courses on LangChain libraries and products, made by the LangChain team.