Deno Sandbox vs Modal Sandboxes

Deno Sandbox

Secrets stay outside the microVM and are substituted only on outbound requests to approved hosts, and an allowlist limits egress. The service is still in beta, sandboxes need the $20 Pro plan, lifetime is capped at 30 minutes, and no sandbox operation appears in the published OpenAPI document.

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.

Deno Sandbox

1. Set DENO_DEPLOY_TOKEN to an organisation token (prefix ddo_) from Settings in console.deno.com. The organisation must be on Pro or above
2. Pass allowNet on every Sandbox.create(). The Security page says outbound access is unrestricted when it is omitted
3. Pass credentials through secrets with a hosts list, not env, so code in the VM sees only a placeholder
4. The default timeout ends the VM when the client disconnects. Pass a duration such as "10m" and reconnect with Sandbox.connect({ id }), up to 30 minutes
5. Create volumes in ord and start the sandbox in ord. A volume mounts only in its own region
6. exposeHttp URLs are public with no authentication. Treat the random subdomain as a secret

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