Email deliverability in 2026: SPF, DKIM, DMARC explained

Since 2024 Google and Yahoo require mandatory SPF, DKIM and DMARC for anyone sending >5,000 emails/day. For SMEs below this threshold not mandatory, but without them 30-60% of emails go to spam. Setup is 1 hour, ROI huge.

What they are and what for

• SPF (Sender Policy Framework): declares which servers can send email for your domain
• DKIM (DomainKeys Identified Mail): cryptographic signature of emails to prove authenticity
• DMARC (Domain-based Message Authentication): rule for what to do if SPF/DKIM fails (quarantine/reject)

SPF setup (DNS record)

Add a TXT record in your DNS:

Type: TXT
Name: @
Value: v=spf1 include:_spf.google.com include:sendgrid.net ~all

Replace _spf.google.com and sendgrid.net with providers you use (Mailchimp: spf.mandrillapp.com, Brevo: spf.brevo.com, etc.).

DKIM setup

Each email provider generates the DKIM key in their dashboard. You copy 1 DNS record (usually CNAME or TXT) as provided. Google Workspace example:

Type: TXT
Name: google._domainkey
Value: v=DKIM1; k=rsa; p=MIGfMA0GCS...

DMARC setup (start in monitor mode)

Type: TXT
Name: _dmarc
Value: v=DMARC1; p=none; rua=mailto:dmarc@yourdomain.com; pct=100

Start with p=none (monitor only) for 1-2 weeks, then move to p=quarantine, finally p=reject after 30 days.

Setup verification (free)

• MXToolbox (mxtoolbox.com): SPF, DKIM, DMARC tests
• Mail-tester.com: send test email, get 0-10 score with issues
• Google Postmaster Tools: monitor domain reputation over time

Realistic result: moving from 30-60% inbox rate to 90-95%. For anyone sending newsletters or transactional emails, this is the first ROI investment. Setup included in AI Email Boost €890.

Want to apply this to your SME?

If you'd like a concrete analysis of your situation, request the free audit from Gamerbit. In 48 hours we tell you exactly where you're losing leads, time or budget — no sales pitch.

For a complete system, the 2026 no-brainer offers are the most direct starting point.