Glossary · Marketing, CRM & Growth
DKIM
Overview
What DKIM is
DKIM, or DomainKeys Identified Mail, is an email authentication method that lets a domain cryptographically sign the messages it sends. The signature proves two things to the receiver: that the email genuinely originated from the domain, and that key parts of it were not altered in transit. It's a foundational defense against email spoofing and tampering.
How DKIM works
The sending server generates a signature using a private key and adds it to the email's headers. The domain publishes the matching public key in a DNS record. When the message arrives, the receiving server retrieves that public key, recomputes the signature, and confirms it matches. If it does, the email passes DKIM; if the content was changed, verification fails.
Why it matters for your business
DKIM rarely works alone—it pairs with SPF and is enforced by DMARC. Together they protect a domain's reputation and keep legitimate email out of spam folders. In email marketing and deliverability projects, a team generates DKIM keys, publishes the DNS record, and verifies signing across every sending source, from your marketing platform to transactional and reactivation campaigns.
Where we use it
Related Zen in Tech services
How our team puts DKIM to work in real projects.
FAQ
DKIM — common questions
What does DKIM do?
DKIM attaches a cryptographic signature to outgoing email so recipients can verify the message truly came from your domain and wasn't tampered with in transit. It strengthens trust and improves deliverability.
DKIM vs SPF?
SPF checks whether the sending server is authorized for the domain; DKIM verifies the message content with a cryptographic signature. SPF validates the path, DKIM validates the message—use both, since each catches what the other misses.
Do I need DKIM?
Yes. DKIM is expected for reliable email delivery, and major mailbox providers require authentication from bulk senders. Setting it up alongside SPF and DMARC protects your domain and inbox placement.
Need DKIM done right?
Book a free consultation and we’ll map the fastest, most cost-effective path for your project.
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