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How Custom Domains Work for Deployed Applications

How custom domains map to a deployment platform using DNS CNAME records — including Runex’s cname.runex.cloud target and HTTPS expectations.

2026-09-24 · 2 min read

Direct answer

A custom domain points your hostname (for example app.example.com) at a deployment platform so visitors reach your app on your brand domain instead of the platform’s default hostname. On Runex, create a DNS CNAME to cname.runex.cloud, then attach the domain to a deployment in the dashboard.

Platform URL vs custom domain

| | Platform URL | Custom domain | | --- | --- | --- | | Example | https://my-app.runex.cloud | https://app.example.com | | DNS you manage | None | CNAME (or apex alternative) | | Typical target | n/a | cname.runex.cloud |

How DNS fits in

Your deployment already exists on the platform.
You create a CNAME at your DNS provider.
The platform associates that hostname with your deployment.
HTTPS is provisioned for the hostname when the platform supports it (Runex provides HTTPS for supported public deployments).

Example record

Type:  CNAME
Name:  app
Value: cname.runex.cloud

Apex domains

Some DNS providers cannot place a CNAME on the zone apex (example.com). Options usually include ALIAS/ANAME/CNAME flattening — follow your DNS provider’s guidance, or use a subdomain like www or app.

Troubleshooting

NXDOMAIN / wrong target: confirm the CNAME value is exactly cname.runex.cloud.
Stale DNS: wait for TTL; check with dig or your provider’s DNS tools.
HTTPS pending: domain must be attached in Runex after DNS is correct.

Full product steps: Custom domains documentation.

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