What your app cannot do yet

Code-execution sandboxes are not available on Outer; use build-time work, queues, or an external API instead.

Code-execution sandboxes are not available. Do not ask for features that run untrusted code inside your app. There is no container runtime behind apps today.

What to ask for instead

You want	Ask for
Run code at request time	Compute it at build time and ship the result as static data
Slow or flaky work	A Background job with retries
Call a code runner	An HTTP call to an external execution API, with the key in Secrets

If container support lands, this page will say so.

For the technical detail, your builder reads Avoid sandboxes.