Here you’ll find answers to “How do I...?” types of questions. These guides are goal-oriented and concrete; they're meant to help you complete a specific task. For conceptual explanations see the Conceptual guide. For end-to-end walk-throughs see Tutorials. For comprehensive descriptions of every class and function see the API Reference.
Installation¶ LangGraph¶ Controllability¶LangGraph.js is known for being a highly controllable agent framework. These how-to guides show how to achieve that controllability.
LangGraph.js makes it easy to persist state across graph runs. The guides below shows how to add persistence to your graph.
See the below guides for how-to add persistence to your workflow using the Functional API:
LangGraph makes it easy to manage conversation memory in your graph. These how-to guides show how to implement different strategies for that.
Human-in-the-loop functionality allows you to involve humans in the decision-making process of your graph. These how-to guides show how to implement human-in-the-loop workflows in your graph.
Key workflows:
interrupt function.interrupt function.Other methods:
interrupt function instead.graph.update_state method. Use this if implementing a human-in-the-loop workflow via static breakpoints.NodeInterrupt: Not recommended: Use the interrupt function instead.See the below guides for how-to implement human-in-the-loop workflows with the Functional API:
Time Travel¶Time travel allows you to replay past actions in your LangGraph application to explore alternative paths and debug issues. These how-to guides show how to use time travel in your graph.
Streaming¶LangGraph is built to be streaming first. These guides show how to use different streaming modes.
Subgraphs allow you to reuse an existing graph from another graph. These how-to guides show how to use subgraphs:
See the multi-agent tutorials for implementations of other multi-agent architectures.
See the below guides for how-to implement multi-agent workflows with the Functional API:
See the below guide for how-to build ReAct agents with the Functional API:
LangGraph Platform¶This section includes how-to guides for LangGraph Platform.
LangGraph Platform is a commercial solution for deploying agentic applications in production, built on the open-source LangGraph framework. It provides four deployment options to fit a range of needs: a free tier, a self-hosted version, a cloud SaaS, and a Bring Your Own Cloud (BYOC) option. You can explore these options in detail in the deployment options guide.
Tip
Learn how to set up your app for deployment to LangGraph Platform:
LangGraph applications can be deployed using LangGraph Cloud, which provides a range of services to help you deploy, manage, and scale your applications.
Assistants are a configured instance of a template.
Threads¶ Runs¶LangGraph Cloud supports multiple types of runs besides streaming runs.
Streaming the results of your LLM application is vital for ensuring a good user experience, especially when your graph may call multiple models and take a long time to fully complete a run. Read about how to stream values from your graph in these how to guides:
With LangGraph Platform you can integrate LangGraph agents into your React applications and colocate UI components with your agent code.
When creating complex graphs, leaving every decision up to the LLM can be dangerous, especially when the decisions involve invoking certain tools or accessing specific documents. To remedy this, LangGraph allows you to insert human-in-the-loop behavior to ensure your graph does not have undesired outcomes. Read more about the different ways you can add human-in-the-loop capabilities to your LangGraph Cloud projects in these how-to guides:
Graph execution can take a while, and sometimes users may change their mind about the input they wanted to send before their original input has finished running. For example, a user might notice a typo in their original request and will edit the prompt and resend it. Deciding what to do in these cases is important for ensuring a smooth user experience and preventing your graphs from behaving in unexpected ways. The following how-to guides provide information on the various options LangGraph Cloud gives you for dealing with double-texting:
LangGraph Studio is a built-in UI for visualizing, testing, and debugging your agents.
These are the guides for resolving common errors you may find while building with LangGraph. Errors referenced below will have an lc_error_code property corresponding to one of the below codes when they are thrown in code.
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