Arbitrary text with specific uses.
WHAT THEY HOLD
Text. What matters is what reads it.
THE COMMON USES
SPF, listing which servers may send mail for your domain DKIM, holding a cryptographic key for signing mail DMARC, stating a policy for mail failing authentication Domain verification for third-party services
SPF
One record only. Two SPF records is an error and causes both to fail.
If you add a sending service, add its mechanism to the existing record rather than creating a second.
DKIM
A long value provided by whoever signs your mail. Add it exactly, without modification.
The value is a key; a single altered character breaks it.
DMARC
Published at _dmarc.yourdomain.com. Start with a monitoring policy rather than one that rejects.
VERIFICATION RECORDS
Search Console, business profiles, payment gateways and email services all use these.
They are the records most often lost during a DNS migration, and the loss is silent until verification lapses.
CHECKING
A lookup for TXT records on your domain shows everything published.
