LangGraph Checkpointing

A checkpoint is saved at every superstep boundary keyed by thread_id — enabling pause, resume, and time-travel

LangGraph Checkpointing A checkpoint is saved at every superstep boundary keyed by thread_id — enabling pause, resume, and time-travel 01 / Graph run 02 / Pause / resume / travel 03 / Outcomes Start · thread_id · Graph run 01 Start thread_id Superstep · run nodes · Graph run · channels 02 Superstep run nodes channels Checkpoint · save @ thread_id · Graph run · barrier 03 Checkpoint save @ thread_id barrier Complete · final state · Graph run 04 Complete final state Paused · await resume · Pause / resume / travel · latest Paused await resume latest Fork · earlier checkpoint · Pause / resume / travel · time-travel Fork earlier checkpoint time-travel next superstep pause resume latest Legend active state waiting terminal success failure / exit

Save every step

  • • A checkpoint marks each superstep boundary
  • • State is keyed by thread_id, not by run
  • • The checkpointer is pluggable (memory, SQLite, Postgres)

Pause & resume

  • • A run can pause with its state fully durable
  • • Resume rehydrates from the latest checkpoint
  • • No in-memory session is required to continue

Time travel

  • • Any earlier checkpoint can be replayed
  • • Forking creates a new branch of history
  • • The original thread is left untouched

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