# Email deliverability field guide

> SPF, DKIM, DMARC, one-click unsubscribe, and low complaint rates remain the floor. Modern ESPs automate DNS setup; they do not replace engaged audiences.

- **Updated:** 2026-05-30
- **Author:** @deliver_ana

## Authentication basics

SPF lists servers allowed to send for your domain. DKIM signs messages cryptographically. DMARC tells receivers how to handle failures and where to send reports. Gmail and Yahoo expect alignment for bulk senders.

Brew, Resend, Klaviyo, and SendGrid provide DNS records when you add a domain. Verify with Gmail Postmaster Tools and third-party inbox tests before scaling volume.

## Reputation and engagement

Mailbox providers track complaints, bounces, and engagement signals. Warm new domains gradually. Send wanted mail to engaged segments first.

## Pre-send checklist

Confirm authentication passes alignment tests. Include one-click unsubscribe headers on marketing mail. Provide a plain-text part. Suppress hard bounces and long-term non-openers. Monitor complaint rates after ESP or template changes.

## FAQ

### Does AI-generated copy hurt deliverability?

Content quality affects engagement, which affects reputation. Providers do not penalize AI by default. They penalize mail people mark as spam.

### Where can I read official Gmail rules?

Start with Google sender guidelines at support.google.com and Yahoo sender best practices. RFC 7489 covers DMARC.

**Canonical:** https://marketinginbox.co/guides/email-deliverability