Directed Graphs vs State Machines

LangGraph is technically a StateGraph. It combines concepts from Directed Graphs and Finite State Machines (FSM).

Visual Comparison

graph TD
    subgraph DAG [Directed Acyclic Graph]
    A1[Start] --> B1[Process] --> C1[End]
    end
    
    subgraph FSM [Finite State Machine]
    S1((Idle)) -- Event --> S2((Active))
    S2 -- "Success" --> S3((Done))
    S2 -- "Error" --> S1
    end

The LangGraph Hybrid

LangGraph uses the Nodes of a Graph to represent the States of an FSM.

• When executing Node A, the system is in "State A".
• The Edges represent the transitions.

This hybrid approach gives you the visual clarity of a flowchart (Graph) with the cyclic power of an FSM.