Definition
A mobile email preview checklist is a structured set of verification steps performed before every campaign send to confirm the email renders correctly and is usable on mobile devices. Since mobile accounts for approximately 50 to 60 percent of email opens across most audiences, skipping mobile testing risks delivering a broken experience to the majority of subscribers.
The checklist goes beyond checking whether the layout fits — it verifies that text is readable without zooming, tap targets are large enough, CTAs remain prominent on small screens and interactive elements function correctly on touch devices.
Key Mobile Checklist Items
- Does the email render at 320px width without horizontal scrolling?
- Is body text at least 14px and readable without pinch-to-zoom?
- Are buttons and links at least 44x44 pixels for comfortable tapping?
- Do images scale correctly and maintain aspect ratios?
- Does the plain-text version display correctly on text-only email clients?
- Are subject lines and preheader text not truncated on common mobile screen widths?
Best Practices
- Test on real devices, not just browser-based responsive previews — email client rendering differs significantly
- Maintain a small set of test devices representing your subscriber base's most common platforms
- Add mobile checklist items discovered through subscriber feedback to prevent recurring issues
- Run the checklist for every campaign, not just major sends — small template changes can break mobile rendering
Related Glossary Terms
Accessible CTA (Email)
An accessible CTA is a button or link coded with sufficient colour contrast, visible focus states, descriptive screen-reader text, and a minimum touch target of 44×44 pixels.
Dark Mode
Dark mode in email refers to how email clients render messages when the recipient has dark mode enabled. It affects colour display, image rendering, and readability. Designers use CSS media queries and hybrid coding techniques to control the dark mode appearance.
Drag-and-Drop Email Editor
A drag-and-drop email editor is a visual interface that allows marketers to build email layouts by dragging content blocks into place without writing HTML or CSS code.
Email A/B Test Confidence Level
The confidence level in an email A/B test indicates the probability that the observed result is genuine and not due to random chance, with 95% being the standard threshold.
Email A/B Test Examples
Email A/B test examples show practical testing scenarios that help marketers improve open rates, click-through rates, and conversions through data-driven experimentation.
Email A/B Test Minimum Detectable Effect
The minimum detectable effect (MDE) is the smallest improvement an A/B test can reliably detect given the available sample size, directly affecting how long a test must run.