What Is a DKIM Selector?
A DKIM selector is the label that tells a receiver which DKIM public key to look up for a domain. Without the selector, an outside checker cannot know the exact DKIM DNS name to query.
SPF and DMARC use predictable DNS names. DKIM does not, which is why selector handling matters for audits.
DKIM Selector DNS Pattern
A DKIM record usually lives at:
selector._domainkey.example.com
The selector is the first label. The domain is the domain being authenticated. For example, if the selector is google and the domain is example.com, the DNS lookup target is:
google._domainkey.example.com
DKIM Selector Examples
Common selector names include:
google._domainkey.example.comselector1._domainkey.example.coms1._domainkey.example.comk1._domainkey.example.commandrill._domainkey.example.com
These examples are only hints. A missing guessed selector does not prove DKIM is absent.
How to Find a DKIM Selector
- Check your mail provider's domain authentication screen.
- Look for DKIM CNAME or TXT records.
- Check common provider selectors only as hints.
- Inspect recent signed messages if you control a mailbox that receives mail from the domain.
- Do not assume a missing guessed selector means DKIM is absent.
Why DKIM Selectors Matter
DKIM audits are selector-aware. If an audit knows the selector, it can check the public key record directly. If it does not know the selector, it can only use discovery hints, provider patterns, and supplied selector lists.
That is why a domain can have working DKIM even when a generic checker says it found nothing. The checker may have queried the wrong selector.
How Veldica Handles Selectors
Veldica can use known selectors during Pro audits and can follow provider patterns where they are visible. For deeper coverage details, see the DKIM Discovery Process.
Which path should you use?
| Need | Best path |
|---|---|
| Learn what a DKIM selector is | This guide |
| Need one fixed domain output | Email Domain Trust Audit |
| Need recurring selector-aware checks | Use the Veldica API |
| Need custom implementation | Request a separate partner or custom review |
| Want a free web-checker preview | Email Domain Trust Checker |
Keep Exploring
Use the Workflow Library to browse more guides, comparisons, and integration examples to continue your evaluation.
Use the technical reference when you already know the selector and want audit details.
Learn why selector guessing fails and how discovery works in practice.
Bundle DKIM selector review into a fixed-output domain audit.
Need DKIM coverage for a real domain?
Use known selectors with the Pro audit, or request a fixed-output domain report when you want SPF, DKIM, DMARC, MX, MTA-STS, TLS-RPT, and BIMI reviewed together.