langgraph-persistence

To persist LangGraph state, compile your graph with a checkpointer and invoke it with a config containing a thread_id. This ensures state is saved and reloaded reliably across calls for multi-turn conversations.

A checkpointer persists state per thread_id for individual sessions, while a Store is needed for cross-thread long-term memory. Use a Store to save user preferences or facts shared across multiple separate conversations.

Yes, you can use a Postgres saver as your checkpointer when compiling the graph. This provides durable checkpointing for LangGraph execution, replacing the default in-memory checkpointer for production-grade persistence.

You isolate conversation history by consistently providing a unique thread_id in the invocation config for each user or session. This thread isolation ensures separate histories so state never mixes between users.

Subgraph checkpointer scoping controls whether subgraphs retain state across invocations by setting the checkpointer parameter to False, None, or True. This determines state persistence behavior for nested graph structures.

LangGraph loses conversational context because the graph lacks a configured persistence mechanism. You must compile it with an appropriate checkpointer and provide a thread_id to restore state across runs.