localhost. Upgrade the Cloudflare development dependencies or disable the inspector when you do not need it.
Symptoms
The preview process may hang at:workerd runtime.
Confirm the sandbox generation
Run the following command inside the sandbox:inet6 address indicates that the sandbox is running on Carbon (Mark 3.1).
The presence of IPv6 identifies the sandbox generation during this rollout. It does not by itself prove that Miniflare is affected.
Check for the Miniflare issue
Check which Cloudflare packages the application resolved:localhost resolves to ::1, but the runtime cannot bind the IPv6 loopback address. Older Miniflare versions pass --inspector-addr=localhost:0 to workerd and wait for an inspector-ready event that never arrives.
Confirm the inspector address while the preview process is stuck:
Upgrade Miniflare or Wrangler
The preferred fix is to update the package that provides Miniflare and regenerate the lockfile. The fix is included in:- Miniflare
4.20260601.0and later - Wrangler
4.97.0and later
npm ls miniflare wrangler again to verify the resolved versions. The fixed Miniflare release uses 127.0.0.1 for the runtime inspector instead of relying on localhost resolution.
Disable the inspector
If you cannot upgrade immediately and do not need runtime debugging, disable the inspector in the Cloudflare integration. For an Astro project whose Cloudflare adapter supportsinspectorPort, update astro.config.mjs:
Related Cloudflare fix
Cloudflare fixed the underlying address selection in workers-sdk pull request #14086. The change replaceslocalhost with 127.0.0.1 for the runtime inspector address.
Set up Astro with Blaxel Sandboxes
Configure and expose an Astro development server in a sandbox.
Infrastructure generations
Compare Carbon with earlier Blaxel infrastructure generations.