Alpha Notice: These docs cover the v1-alpha release. Content is incomplete and subject to change.For the latest stable version, see the current LangGraph Python or LangGraph JavaScript docs.
You are attempting to use built-in LangGraph persistence without providing a checkpointer. This happens when a checkpointer is missing in the compile() method of StateGraph or entrypoint.

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Troubleshooting

The following may help resolve this error: 
from langgraph.checkpoint.memory import InMemorySaver
checkpointer = InMemorySaver()

# Graph API
graph = StateGraph(...).compile(checkpointer=checkpointer)

# Functional API
@entrypoint(checkpointer=checkpointer)
def workflow(messages: list[str]) -> str:
    ...
  • Use the LangGraph API so you don’t need to implement or configure checkpointers manually. The API handles all persistence infrastructure for you.