Preview & Testing
Always preview and test your email before exporting. Email rendering varies across clients: what looks perfect in Chrome may break in Outlook.
Desktop preview
The canvas shows a live desktop preview as you build. What you see is close to what Gmail and Apple Mail will render.
Mobile preview
Click the mobile preview toggle to see how the email renders on a phone-sized screen:
- Columns stack vertically
- Images scale to fit
- Buttons become full-width
- Font sizes adjust for readability
Testing checklist
Before exporting, verify:
| Check | What to look for |
|---|---|
| Images | All images load, correct sizes, alt text set |
| Links | All buttons and text links point to correct URLs |
| Buttons | Large enough to tap on mobile (44px+ height) |
| Text | Readable font size (14px+ body), sufficient contrast |
| Colors | Consistent with brand, sufficient contrast ratios |
| Layout | Doesn't break on narrow screens |
| Spelling | No typos in headings, body, or CTA text |
| Preheader | First line of text is meaningful (shown in inbox preview) |
| Total size | Under 102KB HTML (Gmail clips larger emails) |
Email client testing
| Client | Expected rendering |
|---|---|
| Gmail (web) | Excellent (close to preview) |
| Gmail (app) | Good (minor spacing differences) |
| Apple Mail | Excellent (best email rendering) |
| Outlook 365 | Good (some CSS limitations) |
| Outlook desktop | Fair (uses Word engine, limited CSS) |
| Yahoo Mail | Good |
Common issues
| Issue | Fix |
|---|---|
| Images blocked | Set alt text on all images; it shows when images are blocked |
| Layout breaks on Outlook | Use table-based layouts, avoid CSS grid/flexbox |
| Fonts don't render | Use email-safe fonts (Arial, Helvetica, Georgia) |
| Button isn't clickable | Ensure the <a> wraps the entire button, not just the text |
| Email clipped in Gmail | Reduce HTML size below 102KB |
Tip
Send yourself a test email via your email provider (SES, SendGrid) before sending to your list. What you see in the editor preview may differ from what arrives in your inbox.