Free tools
CNAME chain checker
Follow a hostname's aliases and see loops, apex CNAMEs and signs of flattening.
How it works
- Enter the hostname. Use the full name, such as www.example.com, without a URL scheme or path.
- Follow the aliases. The engine reads each CNAME target until the chain ends, a name repeats, a lookup fails, or the limit of ten CNAME queries is reached.
- Read the flags. Review apex aliases, loops, addresses and possible flattening before editing the record at your DNS provider.
Use the free API
No API key required. Omit the Accept header for JSON. These read-only checks share a per-address rate limit; a 429 response means wait before trying again.
curl --get 'https://app.dodomain.io/api/tools/cname-chain' --data-urlencode 'name=www.example.com' -H 'Accept: text/markdown'Connecting a customer domain
DoDomain verifies DNS records inside your product's connect flow. Read the apex-domain guide before asking a customer to point a bare domain at a CNAME target.
Frequently asked questions
What is a CNAME loop?
A loop occurs when following aliases returns to a name already visited. That circular chain never reaches a final target. A depth limit means the check stopped after its maximum number of hops; it does not prove a loop.
Can a CNAME sit at the zone apex?
A standard CNAME cannot coexist with the SOA and NS records required at a zone apex. Some providers offer ALIAS, ANAME or CNAME flattening instead, returning address records to DNS clients.
Can this prove a CNAME is flattened?
No. Addresses without a visible CNAME can indicate flattening or ordinary A/AAAA records. The tool labels flattening as suspected and cannot reveal a hidden target behind a proxy.
Does the checker change my DNS?
No. It only reads public DNS and applies bounded checks. You do not need an account, and a failed lookup is reported as incomplete rather than treated as proof that the record is missing.
Start on the free plan
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