E2B vs Vercel Sandbox

E2B

Firecracker microVM with its own kernel per sandbox. Two major incidents over an hour in September 2026, on sandbox creation and on creating from snapshots.

Vercel Sandbox

Active CPU billing, so waiting on model responses costs only memory. Tied to a Vercel team and project even when called from elsewhere, and access tokens reach the whole team.

E2B

1. Set a timeout when you create a sandbox. The default is 5 minutes
2. Pause rather than kill when you'll come back. Resume takes about a second and nothing is billed while paused
3. Use Secret.fill in network transforms instead of passing API keys into the sandbox environment
4. Pace sandbox creation. Hobby allows 1 a second and 20 running at once
5. Move to the v2 sandbox endpoints. SDK 2.51.0 and later use them by default

Vercel Sandbox

1. Call sandbox.stop() when the task is done. Memory bills until the session ends
2. Use Sandbox.getOrCreate with a name so retries land in the same sandbox
3. Set networkPolicy to deny-all for untrusted code. The default is allow-all
4. Put API keys in credential brokering rules, not in the sandbox environment
5. Pass persistent: false for one-off runs so no snapshot is stored or billed