DKIM Lookup · free
DKIM record lookup
Enter a domain and a DKIM selector to see the published public key, parse the record, and check for common problems (revoked keys, weak key sizes).
What's a selector?
DKIM records live under a subdomain of the form <selector>._domainkey.<yourdomain>. The selector is an arbitrary string chosen by the sender — common ones are default, google, s1, ps1, k1.
To find a domain's active selectors, check the DKIM-Signature: header of a message from that domain — the s= tag is the selector.
For the full setup story, see our 2026 SPF/DKIM/DMARC guide.
Need this in production?
The free tool is great for one-off checks. For automated monitoring, alerting, and an API, see the related Postscale product.
See the Transactional Email API