Tools
DKIM record checker.
Look up a DKIM selector and public key, check the key strength, or probe common selectors for a domain.
How to read your results
The key and its length. We show the public key and grade it. A 2048-bit RSA key is the safe baseline; 1024-bit is weak and worth rotating.
Selector probe. If you didn't supply a selector we tried common provider ones. A miss doesn't mean you have no DKIM, only that the key lives at a different selector. The exact one is in any sent message's DKIM-Signature header (the s= tag).
Revoked or testing. An empty p= means the key is revoked; t=y means it's in testing mode and receivers may ignore it.
Want the full picture? DMARC, SPF and DKIM in plain English explains how DKIM fits in, and the .eml analyzer reads the selector straight from a real message.
Frequently asked questions
- What is a DKIM selector?
- A selector is a label that points to one DKIM public key in your DNS, at selector._domainkey.yourdomain.com. A domain can have several, one per sending system, so you need the selector to look up the matching key.
- How do I find my DKIM selector?
- The selector is in the DKIM-Signature header of a message you sent (the s= tag). If you do not have one handy, this tool probes common provider selectors (selector1, google, k1, and more) to find one.
- How do I check a DKIM record?
- Enter your domain and the selector. dmarcula looks up selector._domainkey.yourdomain.com, shows the public key, and grades its strength. Leave the selector blank to probe common ones.
- What is a good DKIM key length?
- Use at least a 2048-bit RSA key. 1024-bit keys are weak and increasingly rejected; anything shorter should be rotated.
- Why can't a DKIM record be found?
- DKIM keys are not enumerable from DNS, so a record only resolves at the exact selector. A "not found" usually means the selector is wrong, not that DKIM is missing. Check a recent message's s= tag.
This check is a snapshot. dmarcula watches your domain around the clock, reads the DMARC reports for you, and emails you when something changes. Free, no credit card.