LangGraph is an open-source, low-level orchestration framework for building resilient, long-running and stateful language agents and multi-agent systems as graphs. It provides a graph-first programming model (inspired by Pregel and Apache Beam with a NetworkX-like public interface) to define nodes, edges, branching, subgraphs, and durable state, plus checkpointing and recovery APIs for persistence. LangGraph includes prebuilt components, design patterns, examples and documentation to enable production-grade agent workflows, improved observability and debugging, and integrates with the LangChain ecosystem while remaining usable standalone.