Blaxel Sandboxes vs Deno Sandbox

Blaxel Sandboxes

No compute charge in standby, only $0.20 a GB-month of snapshot storage. 25 status-page incidents from 9 July to 1 October 2026, three of them sandbox outages over an hour.

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.

Blaxel Sandboxes

1. Close WebSocket and terminal connections when done. An open connection keeps the sandbox active and billed
2. Set a TTL or idle expiry on throwaway sandboxes. The default is to keep them
3. Set forbiddenDomains or an allow list at creation, with network.firewall for tools that ignore proxy settings. Both can only be set when the sandbox is created
4. Retry only on WORKLOAD_UNAVAILABLE. The error reference says other codes won't succeed on retry
5. Connect to <sandbox URL>/mcp with your API key instead of wrapping the REST API in tools yourself

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