An apex domain (also called the zone apex, root domain, or naked domain) is the top-level domain name in a DNS zone — the domain with no subdomain label prepended. For example, example.com is the apex domain; www.example.com and blog.example.com are subdomains.
The apex domain is special because it must contain the SOA (Start of Authority) and NS record records that define the DNS zone itself. This creates a critical constraint: you cannot place a CNAME record at the apex, because the CNAME record type cannot coexist with SOA and NS records at the same name.
To point an apex domain to a service that only issues a CNAME target (such as a CDN or load balancer), you have two options:
- Use an A record or AAAA record pointing directly to an IP address (the traditional method).
- Use a provider-specific workaround such as Route 53's "Alias record", DNSimple's "ALIAS", or Cloudflare's "CNAME flattening", which resolve the target hostname and return an A/AAAA record at query time.
WarningYou cannot create a CNAME record at your apex domain. Many DNS registrars and tools will reject or ignore such records. Use an A/AAAA record or a provider-specific alias feature instead.
Understanding the apex domain is essential when configuring DNS records for your site, particularly when setting up a bare domain URL or integrating with hosted platforms that publish only hostname targets.