Modal Sandboxes vs Runloop Devboxes

Modal Sandboxes

GPU sandboxes at the same per-second rates as the rest of Modal. No REST API, and the JavaScript and Go SDKs are beta.

Runloop Devboxes

Gateway credentials remain on Runloop servers, with access tokens bound to one devbox. Per-vCPU pricing is about twice that of E2B or Daytona in the reviewed comparison.

Modal Sandboxes

1. Pass timeout= when you create a sandbox. The default lifetime is 5 minutes
2. Set block_network=True or a cidr_allowlist for untrusted code
3. Give a sandbox a name so a retried create raises AlreadyExistsError instead of starting a second one
4. Snapshot the filesystem before the 24-hour limit and start a fresh sandbox from it
5. Catch ResourceExhaustedError from Sandbox.create() on SDK 1.6.0 and later

Runloop Devboxes

1. Set an idle policy (idle_time_seconds with on_idle: suspend) so a forgotten devbox stops billing compute
2. Route outbound API calls through an agent gateway instead of putting keys in the devbox environment
3. Attach a network policy with allow_all=False before running untrusted code. Egress is open by default
4. Restart background services after every resume. Nothing in memory survives
5. Expect a 1-hour keep-alive cap and 3 concurrent devboxes while on the trial