Take a snapshot
mat snapshot $ID --name before-migrationsnap-0b9e4a7c21d85f3e6a14mat snapshots $IDsnap-0b9e4a7c21d85f3e6a14 ready before-migration 412 MiB froze 240 ms 2026-10-30 09:40- A running sandbox is frozen briefly while its memory is written, then keeps running.
mat snapshotsshows how long it was frozen. - A paused sandbox is copied as it is and stays paused.
- A stopped sandbox has no memory to save. Use it once to boot it first.
- A sandbox keeps at most 10 snapshots. Delete one with
mat snapshot rm $ID SNAPSHOTto take another. - Snapshots share unchanged data with the sandbox, so a fresh one is cheap on disk. The size shown counts the shared parts too.
Restore
mat restore $ID snap-0b9e4a7c21d85f3e6a14sb-4f1c9e27a0b3d5c86e12 is paused at snap-0b9e4a7c21d85f3e6a14; it resumes on its next useEverything the sandbox did since the snapshot is lost: files and processes go back to how they were. The sandbox keeps its ID and ends paused at the snapshot's moment. Its next use resumes it with the processes it had then. The snapshot is kept, so you can restore it again.
Fork
NEW=$(mat fork snap-0b9e4a7c21d85f3e6a14)Forking snap-0b9e4a7c21d85f3e6a14...A fork is a new sandbox with the snapshot's files. It boots fresh, with none of the snapshot's processes: copying memory would give two machines the same random state. It gets a new ID, network address, sandbox certificate authority and secret placeholders, and its machine ID and SSH host keys are reset at first boot.
It takes the source sandbox's size and its idle, egress and secret settings. After that it is independent: change or delete either one without affecting the other. A fork counts as a create, so the create rate limit and your quotas apply. It runs on the same host as the snapshot.
What each operation keeps
| Operation | Files | Processes | Sandbox |
|---|---|---|---|
| Restore | As in the snapshot | As in the snapshot | The same sandbox and ID, paused |
| Fork | As in the snapshot | None: it boots fresh | A new sandbox with its own ID |
| Delete the sandbox | Gone | Gone | Its snapshots are deleted too |
Save points, not backups
Snapshots live on the same host as their sandbox. If that host is lost, the sandbox and its snapshots are lost together, and a snapshot whose files are gone shows failed. Deleting a sandbox deletes its snapshots. Keep what matters in git, or copy it out with mat cp.
Snapshots are not billed yet.
Commands: CLI reference. Routes: API reference.