DNS

DNS connects a domain such as app.example.com to the server that runs your Coolify resource. Coolify configures the resource route and proxy, but you create and manage DNS records with your DNS provider.

Point each domain to the server where the application or service runs, not to the server that runs the Coolify dashboard.

Point a domain to the server

1. Open the resource in Coolify and identify its server.
2. Copy the server's public IPv4 address. If you use IPv6, copy its public IPv6 address as well.
3. Open the DNS zone with the provider that manages your domain.
4. Create the DNS record for the hostname you want to use.
5. Wait until public DNS resolvers return the new value.
6. Follow Add a custom domain to configure the matching URL in Coolify and redeploy the resource.

For example, to use app.example.com with a server at 203.0.113.10, create this record:

DNS providers use different names for the Name field. Some display the complete hostname instead of app.

You can point several root domains and subdomains to the same server IP address. The Coolify Proxy uses the requested hostname to route each request to the correct resource.

Choose the DNS record

Create an AAAA record only when the server and its network path accept IPv6 traffic. If a hostname has both A and AAAA records, both addresses must reach the same intended resource path. A broken IPv6 path can cause domain or certificate requests to fail even when IPv4 works.

For a self-hosted Coolify dashboard domain, point the record to the server that runs the Coolify instance. Then follow Set the Coolify dashboard domain to configure the URL.

Verify the DNS change

DNS changes may take time to propagate because resolvers cache the previous result. Check the public result before troubleshooting Coolify.

Run the following command from your computer, replacing the hostname with your domain:

dig +short app.example.com A

The output should contain the public IPv4 address of the server that runs the resource. If you created an AAAA record, check it separately:

dig +short app.example.com AAAA

You can also query the default Coolify validation resolver directly:

dig @1.1.1.1 +short app.example.com A

If the result is empty or shows an unexpected address, check the record name, value, and DNS zone at your provider. If the result is correct but the domain does not open, confirm that:

• the resource uses the same domain in Coolify
• the domain points to the server where that resource runs
• ports 80 and 443 are open on the server
• the Coolify Proxy is running on the server
• the application listens on the container port configured in Coolify

Configure wildcard DNS

A wildcard DNS record lets multiple subdomains resolve to the same server without a separate record for each name. For example, create this record to send subdomains of example.com to 203.0.113.10:

The wildcard record covers matching subdomains, but it does not cover the apex domain example.com. Create a separate record for the apex domain when you also use it.

After the wildcard record resolves to the server, follow Use generated domains to configure Wildcard Domain and generate application URLs in Coolify.

Preview deployments can generate additional subdomains from the application's preview URL template. Make sure the DNS records cover those names before relying on the generated preview URLs. See Preview Deployments for the preview-specific setup.

Configure Coolify DNS validation

Coolify can check application domains and the self-hosted instance URL against public DNS. DNS validation is enabled by default.

Open Settings > Configuration > Advanced to manage:

• DNS Validation: enables or disables the check.
• Custom DNS Servers: sets the resolvers used for the check. The default is 1.1.1.1. Enter a comma-separated list of IPv4 or IPv6 resolver addresses, such as 1.1.1.1,8.8.8.8, or leave the field empty to use the system resolvers.

Current DNS validation checks the domain's A records. Validation succeeds when an address matches the selected server's IPv4 address or a recognized Cloudflare proxy address. Coolify skips this check for generated sslip.io domains.

DNS validation reports a mismatch, but it does not replace a public DNS check. A cached resolver result, an incorrect AAAA record, firewall rules, or a proxy configuration can still prevent the domain from working.

Use internationalized domain names

Convert domains that contain non-ASCII characters to Punycode before you create DNS records or enter the domain in Coolify.

For example, use xn--mnchen-3ya.example.com for münchen.example.com. Some DNS providers perform this conversion automatically, but the DNS record and the domain saved in Coolify must resolve to the same hostname.

Related networking guides

If DNS resolves correctly but HTTPS still fails, follow Let's Encrypt troubleshooting.