LangGraph

What Is LangGraph?

LangGraph extends LangChain's capabilities for building sophisticated workflows. While chains assume linear execution, LangGraph supports arbitrary control flow: loops, conditional branches, and cycles. This is essential for implementing complex workflows where decisions at one step affect downstream steps.

LangGraph introduces the concept of a "graph" where nodes represent operations (calling an LLM, tool use, human input) and edges define the flow between operations. You can create feedback loops where an agent reflects on its output and revises it, or where multiple agents iterate on solutions together. State is explicitly managed, passing information between nodes.

LangGraph is particularly valuable for agentic systems that require reasoning loops, where the agent generates a response, evaluates it, and iterates for improvement. It's also useful for multi-step workflows with complex decision logic that can't be expressed as a simple chain.