TXT Record Lookup returns the free-form text records published on a domain. TXT started as a place to leave notes in DNS and became the general-purpose slot for anything that needs to prove control of a domain or publish policy. In practice most TXT records fall into two groups. The first is domain verification: Google, Microsoft, Meta and others ask you to publish a token so they can confirm you own the name. The second is email authentication, where SPF, DKIM and DMARC all live as TXT records with specific syntax at specific names. A domain can hold many TXT records at once and they do not interfere with each other, with one important exception: exactly one SPF record is allowed, and a second one makes both invalid. Individual strings are capped at 255 characters, so longer values such as DKIM public keys are split into several quoted chunks that resolvers join back together. For the email records specifically, use SPF Record Checker, DMARC Record Checker and DKIM Record Lookup, which query the right name and validate the syntax rather than just printing the raw string.
DNS resolution happens in multiple stages. When you type a domain name, your browser first checks its own cache, then the OS resolver cache, then queries your configured DNS resolver (usually your ISP or a public resolver like 8.8.8.8 or 1.1.1.1). If none have the record cached, the resolver performs a recursive query: it asks the root name servers for the TLD servers (.com, .net, etc.), then asks the TLD servers for the authoritative name servers of the specific domain, and finally asks the authoritative servers for the actual record. This entire process typically completes in under 100ms. DNS-over-HTTPS (DoH) encrypts DNS queries in HTTPS traffic, preventing ISPs and network observers from seeing which domains you query. It was standardized in RFC 8484 in 2018 and is now supported by all major browsers. Google and Cloudflare both operate free public DoH endpoints (dns.google and cloudflare-dns.com). TXT records have become a critical security mechanism: SPF (Sender Policy Framework) records specify which servers are allowed to send email for a domain, DKIM (DomainKeys Identified Mail) records provide public keys for verifying email signatures, and DMARC records tell receiving mail servers what to do when SPF or DKIM checks fail. Checking these records is the first step in diagnosing email deliverability problems.