DKIM stands for DomainKeys Identified Mail.
It’s an email authentication method that helps prove an email really came from the domain it claims to be from—and that it wasn’t altered along the way.
Here’s the plain-English version:
- When an email is sent, the sending mail server adds a digital signature to the message.
- That signature is created using a private key owned by the sender’s domain.
- The receiving mail server looks up the sender’s public key in DNS and checks the signature.
- If it matches ✅ the email is legit and unchanged.
- If it doesn’t ❌ the message may be spam, spoofed, or tampered with.
Why DKIM matters
- Helps prevent email spoofing (fake “from” addresses)
- Improves email deliverability (less likely to land in spam)
- Builds trust with providers like Gmail, Outlook, Yahoo
DKIM vs SPF vs DMARC (quick vibe check)
- SPF: “Is this server allowed to send mail for this domain?”
- DKIM: “Was this email really signed by this domain, and not modified?”
- DMARC: “What should we do if SPF/DKIM fail?” (policy + reporting)
