DKIM Checker
Query {selector}._domainkey.{domain} for the DKIM TXT public key.
About the DKIM Checker
The DKIM Checker queries the DKIM public key TXT record for a domain and selector, showing you the key algorithm, size, flags and full public key. DKIM (DomainKeys Identified Mail) is the cryptographic half of modern email authentication — it puts a signature on every outbound message using a private key held by your mail server, and receivers verify that signature against the public key you publish in DNS.
Because DKIM keys live at selector-specific hostnames (`selector._domainkey.yourdomain.com`), verifying setup means knowing which selectors your mail platform uses. Google Workspace uses `google` by default; Microsoft 365 uses `selector1` and `selector2`; Mailchimp uses `k1`; SendGrid uses `s1` and `s2`. This tool lets you enter any selector and confirm the key is published, well-formed and using a modern key size (2048-bit RSA is today's standard).
Use DKIM Checker whenever you set up a new sending platform, rotate keys as part of your security hygiene, or debug why a domain's DMARC is failing. A missing or malformed public key silently breaks DKIM verification, which cascades into DMARC failure and inbox-placement problems.
How to use this tool
- 1Enter the required value in the input field above (domain, IP, URL, or text depending on the tool).
- 2Click the action button to run the check — results are computed instantly from our edge network.
- 3Review the parsed output, key fields and any warnings shown in the result card.
- 4Copy the result, share the page URL, or jump to a related tool from the sidebar to continue debugging.
Key features
- Selector-aware lookup — supports any provider
- Key size and algorithm display
- Detects revoked keys (empty p= value)
- Handles multi-string TXT records (long 2048-bit keys)