What is a DKIM selector?

A selector identifies the DKIM key pair used by a mail provider. It is the first label before _domainkey.

Where do I find the selector?

Look in your email provider's domain authentication screen or DNS setup instructions.

Not reliably. A domain can publish many DKIM selectors, so the selector is required for an exact lookup.

DKIM tool

Query selector._domainkey.yourdomain.com and confirm whether a usable DKIM public key is present.

SenderDNSReceiver

DKIM

Enter a domain to run the check.

The tool queries the selector you provide, checks for a DKIM TXT record, detects duplicate selector records, and looks for a usable public key tag.

Copy the exact selector from your mail provider. Common selectors include google, selector1, selector2, default, k1, and s1.