TXT Record

A TXT record is a DNS record type that holds arbitrary text. Originally intended for human-readable information, TXT records have become the standard container for machine-readable data used in email authentication, domain ownership verification, and service configuration.

What TXT Records Are Used For

Because TXT records have no enforced structure, they have become a universal attachment point for any service that needs to publish metadata about a domain. Common uses include:

• SPF (Sender Policy Framework) — a TXT record at the root of your domain listing which mail servers are authorized to send email on your behalf. Receiving servers check this during SMTP to detect forged senders.
• DKIM public keys — each DKIM signing key is published as a TXT record at a subdomain like selector._domainkey.example.com. Receiving servers fetch this to verify email signatures.
• DMARC policy — published at _dmarc.example.com, specifying how receivers should handle messages that fail SPF or DKIM alignment.
• Domain ownership verification — services like Google Search Console, certificate authorities, and SaaS providers ask you to add a specific TXT record to prove you control the domain.
• Other service metadata — DMARC reporting addresses, Apple MDM enrollment, and various other protocols use TXT records to publish configuration.

The 255-Character String Segment Limit

The DNS wire format limits each individual string within a TXT record to 255 bytes. However, a single TXT record can contain multiple strings that are concatenated together by the resolver before being returned to the application. This means a TXT record can hold data longer than 255 bytes by splitting it into adjacent quoted strings.

In zone file notation, multiple strings in one record look like this:

example.com. IN TXT "v=spf1 include:_spf.google.com include:sendgrid.net " "include:mailchimp.com ~all"

The two quoted strings are treated as a single concatenated value. Many DNS management UIs handle this splitting automatically when you paste a long value, but it is worth understanding if you are editing zone files directly or if a record lookup returns unexpectedly short text.

Multiple TXT Records at the Same Name

A domain can have multiple TXT records at the same owner name, and resolvers return all of them as a set. Most applications that query TXT records are written to handle this correctly — they scan all returned strings looking for a recognized prefix (such as v=spf1 or v=DMARC1).

One important exception: SPF. RFC 7208 specifies that a domain must not have more than one TXT record beginning with v=spf1. If two such records exist, the SPF lookup result is a permanent error, causing SPF checks to fail for all mail from that domain. This is a common misconfiguration when switching email providers — the old SPF record is not removed when the new one is added.

Common Mistakes

• Leaving stale verification records. Domain verification TXT records for services you no longer use accumulate over time. They do no direct harm, but they clutter your zone and may reveal which services you use.
• Duplicate SPF records. Having two v=spf1 TXT records at the same name causes SPF to return a permanent error (permerror), which many receivers treat as a hard failure. Always merge SPF into a single record.
• Exceeding the SPF lookup limit. SPF permits a maximum of 10 DNS lookups during evaluation. Each include:, a:, and mx: mechanism counts toward this limit. Exceeding it causes a permerror regardless of how many TXT records you have.

Query TXT records with the DNS tool →