Custom preview domains let your sandboxes and computers appear at <slug>.your-domain.com instead of <slug>.miosa.app. Your users see your brand at every URL, with no MIOSA branding visible.
Add this CNAME record at your DNS provider
That is the entire setup. One record:
| Field | Value |
|---|---|
| Type | CNAME |
| Host | * (wildcard) |
| Value | proxy.miosa.ai |
| TTL | 300 - 600 seconds |
| Proxy status (Cloudflare only) | DNS only - gray cloud |
Within a few minutes, visit any sandbox URL at <slug>.<your-domain> and MIOSA will auto-bind your domain. No further steps in MIOSA’s dashboard required.
How it works
You set one CNAME record. The first time someone visits <slug>.<your-domain> in your tenant, MIOSA’s edge:
- Detects your domain’s CNAME points at us.
- Looks up the slug - confirms it belongs to your tenant.
- Auto-binds
<your-domain>to your tenant. - Issues a TLS certificate for the wildcard.
- Routes the request to your sandbox.
Security note: Slugs are unguessable UUID prefixes, so only the tenant that owns the sandbox can trigger the auto-bind for a given domain.
Troubleshooting
My sandbox URL returns a TLS error or cert warning
- DNS hasn’t propagated yet - wait a few minutes.
- If using Cloudflare, verify proxy status is DNS only (gray cloud).
- Confirm the record exists:
dig +short "*.your-domain.com" CNAME
# Expected: proxy.miosa.ai.My sandbox URL returns 502 or 503
Your sandbox isn’t running, or no HTTP server is listening on the port you’re requesting. The DNS chain is correct - your sandbox just needs to serve traffic.
My sandbox URL returns 400 or “URL not connected”
The slug doesn’t match any sandbox in your tenant. Confirm the sandbox is in running state and that the slug (first 8 hex chars of the sandbox UUID) matches the leftmost label of the hostname.
Disconnecting
To stop using your custom domain: remove the CNAME from your DNS provider, or open Settings → Domains in MIOSA and click Disconnect. After disconnecting, the next request to <slug>.<your-domain> will fail to issue a certificate. The domain becomes available to bind to a different tenant after the cache expires.
Optional - explicit registration via Settings → Domains
If you prefer to register your domain in MIOSA before sending traffic (instead of using auto-discovery), open Settings → Domains and enter your domain. MIOSA will show you the same CNAME instructions and verify DNS on demand. The end result is identical.
See also
- White-Label Setup - branding, logo, accent color
- Domains (Deploy) - per-deployment custom domains and TLS details
- External Attribution - scoping resources to your end-users