Definition
A deliverability checklist is a standardised set of checks performed before every email send to maximise the likelihood of inbox placement. The checklist covers authentication, list quality, content best practices, technical configuration, and sending infrastructure.
Using a deliverability checklist transforms deliverability from reactive troubleshooting to proactive prevention. Every item on the checklist addresses a known factor that mailbox providers use when deciding whether to deliver, reject, or filter your email.
Standard Deliverability Checklist
| Area | Check | Why It Matters |
|---|---|---|
| Authentication | SPF, DKIM, and DMARC passing | Required by Gmail/Yahoo since 2024 |
| List quality | Bounce rate under 2%, no purchased addresses | High bounce rates damage reputation |
| Spam complaints | Rate below 0.1% in last 30 days | Above 0.3% triggers blocking |
| Content | No trigger words, balanced text-to-image ratio | Reduces false-positive filtering |
| Links | All links valid, no blacklisted domains | Broken or malicious links trigger filters |
| Unsubscribe | One-click header present and working | Required for bulk senders |
| Sending volume | Gradual increases, no sudden spikes | Sudden volume spikes trigger throttling |
| Reputation | IP/domain not on any blacklist | Blocklisted IPs are rejected |
| Engagement | Segment engaged subscribers separately | Engaged subscribers get better placement |
Best Practices
- Automate as many checklist items as possible (authentication checks, blacklist monitoring)
- Run the checklist for every campaign, not just major sends
- Document checklist results for compliance and troubleshooting
- Add new checklist items as mailbox provider requirements evolve
- Review and update the checklist quarterly against current best practices
- Train all team members who send email on the checklist process
Related Glossary Terms
Deliverability Audit
A deliverability audit systematically evaluates your email programme's technical setup, sending practices, and content quality to identify and fix inbox placement issues.
Deliverability Myths
Deliverability myths are common misconceptions about what affects email inbox placement — such as 'images cause spam filtering' or 'short emails deliver better' — that lead senders to focus on the wrong factors.
Email Deliverability Testing
Email deliverability testing uses seed lists and inbox placement monitoring to measure what percentage of emails reach the inbox versus the spam folder across major ISPs and mailbox providers.
Delivery Rate
Email delivery rate is the percentage of sent emails that are accepted by the recipient's mail server, distinct from inbox placement rate which measures how many reach the inbox.
Gmail Promotions Tab
The Gmail Promotions Tab is a default inbox category that automatically filters marketing and promotional emails away from the Primary tab, significantly reducing visibility and open rates for commercial senders.
Primary Inbox
Primary inbox refers to the main folder where email clients deliver important messages, as opposed to promotional or social tabs in tabbed inbox systems like Gmail, where placement significantly impacts open rates.
Frequently Asked Questions
An automated deliverability check can run in seconds using tools that verify authentication, check blacklists, and test inbox placement. A thorough manual review takes 5–15 minutes, depending on campaign complexity. The time investment is minimal compared to the cost of poor deliverability.
Authentication verification — ensuring SPF, DKIM, and DMARC are configured and passing — is the single most important check. Without proper authentication, other deliverability efforts are undermined. Since the Google/Yahoo 2024 requirements, authenticated emails are mandatory for bulk senders.