> ## Documentation Index
> Fetch the complete documentation index at: https://opensandbox-oc-s-762ac928075c46d2828bcb22.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# Fork from Checkpoint

Create a new sandbox from a checkpoint.

<ParamField path="checkpointId" type="string" required>
  Checkpoint ID
</ParamField>

<ParamField body="timeout" type="integer">
  Idle timeout for the new sandbox (default: `0` — persistent, never auto-hibernates)
</ParamField>

<ParamField body="envs" type="object">
  Environment variables to override on the fork. Keys that match the checkpoint's stored envs are replaced; new keys are added.
</ParamField>

<ParamField body="secretStore" type="string">
  Name of a secret store to attach. If the checkpoint already has a store, secrets are merged — the new store's values win on collision and egress allowlists are aggregated.
</ParamField>

<ParamField body="memoryMB" type="integer">
  Memory for the forked sandbox, in MB. Clamped to a valid range: the floor is the checkpoint's own memory (a fork can't start smaller than the snapshot it restores, so a smaller value is ignored) and the ceiling is 16384 (16 GB; larger values are capped). The `memoryMB` field in the response reports the effective value after clamping.
</ParamField>

<ResponseExample>
  ```json 201 theme={null}
  {
    "sandboxID": "sb-def456",
    "status": "running",
    "region": "use2",
    "workerID": "w-use2-abc123",
    "memoryMB": 4096
  }
  ```
</ResponseExample>