StateGraph

StateGraph is the builder that holds a state schema, named nodes, and edges. It describes the workflow; compile() turns that description into something you can run.¹

Tiny example

from typing_extensions import TypedDict
from langgraph.graph import StateGraph

class OrderState(TypedDict):
    order_id: str
    status: str

builder = StateGraph(OrderState)

Think of builder as a whiteboard. You still need to add work and routes.

Object	Job
`StateGraph(OrderState)`	Starts the definition
`builder.add_node(...)`	Registers work
`builder.add_edge(...)`	Registers routing
`builder.compile()`	Produces the runnable graph

Failure note

Creating StateGraph does not call a model, save state, or run anything. Do not confuse the builder with the compiled graph.

LangChain, Graph API overview. ↩