Email deliverability checklist
Gmail, Yahoo and Microsoft now publish clear rules for anyone who sends in volume. Tick these off and most delivery problems disappear.
Quick answer
Authenticate your domain with SPF, DKIM and DMARC, add one-click unsubscribe, keep spam complaints below 0.1% and bounces at or under about 2%, send only to verified, opted-in addresses, keep volume steady, and monitor everything in Google Postmaster Tools.
Free tool: test your domain's records with the MX, SPF, DKIM and DMARC checker.
1. Authentication
- ☐ SPF record lists every service that sends for your domain.
- ☐ DKIM signing turned on in each sending service.
- ☐ DMARC record published (at least
p=none), and your From domain aligns with SPF or DKIM. - ☐ Sending servers have valid forward and reverse DNS, and use TLS.
Gmail (for senders of more than 5,000 a day to Gmail users) and Yahoo (for bulk senders) have required this since February 2024, and Microsoft added similar rules for Outlook.com in May 2025.
2. Unsubscribe
- ☐ One-click unsubscribe (List-Unsubscribe headers, RFC 8058) on marketing email.
- ☐ A visible unsubscribe link in the email itself.
- ☐ Unsubscribes processed within 2 days (Gmail and Yahoo), and never later than 10 business days (US law).
3. List quality
- ☐ Addresses collected with consent, ideally double opt-in.
- ☐ No bought or rented lists.
- ☐ List verified before large sends. See how to clean a list.
- ☐ Hard bounces removed immediately.
- ☐ Inactive subscribers re-engaged or removed (sunset policy).
4. Numbers to stay within
| Metric | Target |
|---|---|
| Spam complaint rate | Below 0.1%; never 0.3% or higher (Gmail); below 0.3% (Yahoo) |
| Bounce rate | At or under about 2% |
5. Sending habits
- ☐ Steady volume; increase gradually rather than in sudden spikes.
- ☐ Cold outreach from separate, warmed-up inboxes. See cold email limits.
- ☐ Consistent From name and address people recognize.
6. Content
- ☐ Honest subject lines that match the content.
- ☐ A sensible balance of text and images; never a single big image.
- ☐ No link shorteners; links point to your own domain where possible.
- ☐ Your physical postal address in marketing email (US law).
- ☐ Test with tools such as mail-tester.com before big campaigns.
7. Monitoring
- ☐ Google Postmaster Tools set up for your domain (spam rate and compliance).
- ☐ DMARC reports reviewed for unknown senders using your domain.
- ☐ Bounce and complaint rates checked after every send.
Questions people ask
- Do these rules apply to small senders?
- The strict requirements apply to bulk senders (5,000+ a day to Gmail or Outlook.com users), but Gmail asks all senders to set up SPF or DKIM, and following the full list helps everyone.
- What does mail-tester's "header from different domains" warning mean?
- Your From address uses one domain while the message is sent or signed by another. Set up DKIM for your own domain in your sending service so the domains align.
- Does email open rate affect deliverability?
- Engagement matters. Providers watch how people react: opens, replies, deletions without reading and spam reports. Sending to people who never open drags your placement down.