Save checkpoints, experiment freely, travel back in time.

A visual demo of Sandbox SDK's snapshot/restore feature. Create save points like in a video game - run dangerous commands without fear, then restore when needed.

• Interactive terminal UI
• One-click checkpoint saving
• Instant restore to any checkpoint
• Pre-built "dangerous" command buttons to test recovery

# Create the R2 bucket for storing snapshots
wrangler r2 bucket create time-machine-snapshots

# Enable the localBucket flow for local development
cp .dev.vars.example .dev.vars

# Run
npm install
npm run dev

Open http://localhost:8787 in your browser.

This example supports both backup flows:

• USE_LOCAL_BUCKET_BACKUPS=true enables the local-development localBucket flow
• USE_LOCAL_BUCKET_BACKUPS=false uses the regular production backup flow

wrangler.jsonc defaults USE_LOCAL_BUCKET_BACKUPS to false, so deployed environments keep using the production path.

For local development, copy .dev.vars.example to .dev.vars to enable localBucket by default and showcase the local R2 binding flow.

If you want to test the production-style flow during local development, either delete .dev.vars or set:

USE_LOCAL_BUCKET_BACKUPS=false

When USE_LOCAL_BUCKET_BACKUPS=false, createBackup() uses presigned URLs while wrangler dev still uses local R2 storage by default. Cloudflare's R2 docs note that local Worker development writes to local storage unless the binding is configured with "remote": true, so set "remote": true on the BACKUP_BUCKET binding if you want local development to exercise the production path against a real R2 bucket.

1. Save a checkpoint - Click "Save Checkpoint" to snapshot /workspace
2. Do something dangerous - Try the "Destroy Everything" button
3. Check it's gone - Run ls /workspace to see the damage
4. Restore - Click any checkpoint to go back in time

Under the hood:

• createBackup() always creates the same backup archive structure in R2
• with USE_LOCAL_BUCKET_BACKUPS=true, the example calls createBackup({ localBucket: true }) and restores through the local R2 binding path
• with USE_LOCAL_BUCKET_BACKUPS=false, the example uses the regular production backup flow

• Tutorial Platforms - Reset to lesson start if student breaks something
• AI Coding Agents - Checkpoint before AI makes changes, restore if wrong
• Config Testing - Snapshot before editing configs, restore if broken
• Dev Environments - Share a "golden" environment, everyone starts from same state