Free DKIM Record Checker
Look up and validate any domain's DKIM record. Check selector configuration, parse tags, validate public keys, and get actionable fixes.
Discovered Selectors
DKIM Record
Issues
Recommendations
What is DKIM?
DomainKeys Identified Mail (DKIM) is an email authentication method that allows the sender to digitally sign messages using a private key. The receiving mail server then verifies the signature by looking up the corresponding public key published in DNS. This proves the message hasn't been tampered with in transit and confirms the sender's identity.
Unlike SPF and DMARC, DKIM records require a selector — a label
chosen by the sender — because the public key is published at
<selector>._domainkey.yourdomain.com.
This allows domains to use multiple keys simultaneously (e.g. one per email provider)
and rotate keys without downtime.
Tag Quick Reference
| Tag | Description |
|---|---|
| v | Version — should be "DKIM1" |
| k | Key type — "rsa" (default) or "ed25519" |
| p | Public key data (base64-encoded) — required |
| h | Acceptable hash algorithms (sha1, sha256) |
| s | Service type — "*" (all, default) or "email" |
| t | Flags — "y" (testing) or "s" (strict alignment) |
| n | Notes — human-readable comments |
Common Selectors
Each email provider uses its own selector. Here are some of the most common ones:
| Selector | Provider |
|---|---|
| Google Workspace | |
| selector1, selector2 | Microsoft 365 |
| default | Various / generic |
| k1 | Mailchimp |
| Various SMTP providers | |
| dkim | Generic / self-hosted |
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