DKIM Checker
Look up your DKIM record, detect published selectors, validate the public key and flag weak keys - so you know your mail is properly signed. Free, no signup.
Selector detection
Probes common selectors (Google, Microsoft, Mailchimp…) to find your published DKIM keys.
Public key
Retrieves and parses the p= public key from your DKIM TXT record.
Key strength
Warns on weak keys below 1024-bit, which modern providers may reject.
Missing records
Tells you if no DKIM is published so unsigned mail can be fixed before it bounces.
DKIM FAQ
What is a DKIM selector?
A selector is a label (e.g. google._domainkey) that points to a specific DKIM public key in DNS, letting you rotate keys and run several senders. This tool probes the selectors common providers use.
Why can't DKIM be found?
DKIM is only discoverable if you know the selector. If yours uses a custom selector we don't probe, the record may still exist - check your email provider's DKIM setup for the exact selector name.
Related email tools
More email and DNS security tools
SPF Checker
Check an existing SPF record for errors and lookup limits.
DMARC Checker
Validate an existing DMARC record and see how it is configured.
Email Security Checker
Run SPF, DKIM and DMARC checks together in one report.
MX Lookup
Look up the mail servers for any domain.
DNS Lookup
Look up A, AAAA, MX, TXT, NS and other DNS records for any domain.
This is one layer of the scan
FreeThis DKIM Checker scan covers one category. A full scan adds the checks it does not reach: exposed secrets, malicious scripts, and supply chain risks in your third-party code.