DNS record types

What is a TXT record?

A TXT record holds free-form text, and in practice carries SPF, DKIM, DMARC and domain-ownership verification.

TXT was designed for human-readable notes and became the place the internet keeps machine-readable policy. A domain typically has several: one SPF record, several verification strings, and DKIM keys under _domainkey.

Example

example.com.  3600  IN  TXT  "v=spf1 include:_spf.google.com ~all"

The mistake people make

A single TXT string cannot exceed 255 bytes. Longer values are stored as several strings that must be joined with nothing between them — every real DKIM key and most SPF records are split this way. Tools that join on a space corrupt the value while still showing something that looks correct.

Check the TXT records on a real domain, with everything else that can quietly break.

Check a domain