Apex CNAME, ALIAS and flattening explained

Why there's no CNAME at the apex

A CNAME says "this name is an alias for another name", so the DNS standard doesn't allow other records alongside it. The zone apex always has SOA and NS records, so a real CNAME can't live there.

How providers work around it

• CNAME flattening (Cloudflare): you enter a CNAME at the apex, and the provider looks up the target and answers with its A and AAAA records.
• ALIAS or ANAME records (for example Namecheap, DNSimple and DNS Made Easy): a separate record type that behaves the same way.
• Route 53 alias records: point at AWS resources such as CloudFront or load balancers, or at other records in the same zone, but not at arbitrary hostnames.
• Azure alias records: point at Azure resources by resource ID.

What happens when you migrate

None of these are real DNS records, so each provider pair needs a translation. A flattened CNAME can become an ALIAS where the destination has one, a Route 53 alias when the target is CloudFront, or static A/AAAA records as a last resort. Static addresses work, but they won't follow the target if its IPs change, so they're flagged for review.

The migration guides show how each pair handles apex records, and the preview shows the exact translation for every one of yours.

The simplest fix

If your hosting platform supports it, redirect the apex to www and point www at the platform with a normal CNAME. That works at every provider and never needs translating.