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Replay plays one episode of an existing LeRobot dataset straight back onto the arms: the episode’s recorded action column is streamed to the motors frame by frame, then the robot returns to its rest pose. It’s the inverse of data collection — instead of recording teleop actions it reproduces an already-recorded take on the hardware. You can launch it from the web control panel or the CLI (axol replay-dataset). No VR, cameras, or policy server are involved — replay only drives the arms, so the robot config carries no cameras. The arm is first moved to the rest pose (the same collision-aware return-to-rest run-policy uses) so it starts where every recorded episode does: episodes are recorded from rest, so the first replayed action is ~rest and there’s no jump.
Replay drives the arms open-loop from the recorded actions — it does not watch the scene. Make sure the workspace is clear and roughly matches what the episode was recorded in before starting, and keep Stop (or Ctrl+C) within reach. Match the stiffness used at collection time so the arm tracks the same way it did when recorded.

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Before you start

  • Axol installed (one-command install), CAN up, and motors verified.
  • A recorded dataset to replay — either local under --root ($HF_LEROBOT_HOME by default) or pullable from the HuggingFace Hub by its repo_id. See Data Collection to record one.

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Run it

1

Connect the robot

Connect the Axol Host and Axol. No cameras are needed for replay.
2

Select Replay Dataset and fill the fields

Pick Replay Dataset. Set the dataset repo id (e.g. myorg/pick-place), the episode index (0-indexed), the loop toggle, and optionally interpolate (smooths playback by upsampling the recorded actions to ~120 Hz commands; timing is unchanged) — the per-run inputs. Playback fps and stiffness live in the Settings tabs.
3

Start

Clear the workspace, then press Start. The arm moves to rest, replays the episode at the recorded timing, and returns to rest. With loop on it repeats (returning to rest between takes) until you press Stop.

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Next steps

Data Collection

Record the episodes you replay here.

replay-dataset reference

Every flag and the replay internals.