Gmail 2026 sender checklist from a deliverability consultant
I fix inboxes for a living at Inbox Clearance Agency. Every quarter someone asks whether AI tools magically improve placement. They do not. Mailbox providers still score authentication, complaints, and engagement.
Gmail bulk sender guidelines (see support.google.com) expect SPF, DKIM, and DMARC alignment, easy one-click unsubscribe for marketing mail, and spam complaint rates kept low. Yahoo published parallel expectations.
Practical checklist before you scale a new ESP or AI-generated campaign: verify domain in the platform, confirm DKIM rotates correctly, publish DMARC at least p=none with reporting, include List-Unsubscribe headers, warm new domains gradually, segment engaged users first.
Modern ESPs including Brew, Resend, Klaviyo, and SendGrid automate much of the DNS setup. Automation does not replace list hygiene. Sending AI-crafted mail to a stale list still tanks reputation.
Full guide on our site walks RFC 7489 and Litmus placement tests. This thread is the field version I send clients before they flip a big switch.