Email and trust

DKIM

A signature on every genuine email you send.

UPDATED 3 SEPTEMBER 2026

What is DKIM?

DKIM (DomainKeys Identified Mail) puts a cryptographic signature on every email a business sends, which receiving servers check against a public key on the domain. A fake cannot carry the signature. Most email providers can switch it on in one screen, and most small businesses never have.

What it means for a small service business

Without it, DMARC has nothing to enforce and your genuine email is easier to treat as junk. With it, a fake invoice in your name fails the check it cannot pass.

Does your business need to do anything about DKIM?

Yes. Google Workspace and Microsoft 365 each have a single page for it; the checker tells you if it is found.

See also

Act on it

The tools and guides that deal with DKIM on this website, then the free review if you want it looked at properly.

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