Free Cold Email Deliverability Tools

Each one runs a live DNS lookup and tells you what it found. They exist because we needed them: the first of these checks is what told us that growfast.sh had no MX record and seobolt.app had no DMARC record at all.

SPF checker

Reads the live SPF record, resolves every include it points at, and counts the DNS lookups. Over ten, receivers stop evaluating your SPF entirely.

DMARC checker

Reads the record at _dmarc on your domain and explains the policy it publishes — including the cases where a record exists but does nothing.

MX lookup

Resolves the MX records and names the provider behind them — which decides whether an address on this domain can be checked before you send to it.

Deliverability audit

Every check on this site at once, for a domain you are about to send from. It takes about a second and touches nothing but DNS.