Newsletter · Arcane
Scored 94/100 across 21 email clients by the Emailens engine, 169 compatibility warnings (0 error-level), 24.3KB compiled HTML. Last verified .

Per-client compatibility
| Client | Score |
|---|---|
| Apple Mail | 100/100 |
| Apple Mail iOS | 100/100 |
| Samsung Mail | 100/100 |
| HEY Mail | 100/100 |
| Superhuman | 100/100 |
| Outlook 365 | 97/100 |
| Outlook iOS | 97/100 |
| Outlook Android | 97/100 |
| Outlook for Mac | 97/100 |
| Yahoo Mail | 97/100 |
| Thunderbird | 97/100 |
| Gmail | 94/100 |
| Gmail Android | 94/100 |
| Gmail iOS | 94/100 |
| Yahoo Mail Android | 94/100 |
| Yahoo Mail iOS | 94/100 |
| Fastmail | 94/100 |
| Proton Mail | 88/100 |
| AOL Mail | 88/100 |
| Outlook (New) | 76/100 |
| Outlook Classic | 73/100 |
Use it
Notes on this template
The spread is what matters on this template: 100 in Superhuman against 73 in Outlook Classic, a 27-point gap across the same file. 5 of the 21 clients render it without a single flagged property. Outlook Classic is the one to preview against after any edit, because it is where this template has the least margin, and the 169 warnings behind that score are concentrated there rather than spread evenly.
At 24.3KB compiled it has roughly 78KB of headroom before Gmail clips the message at 102KB and hides the rest behind a "View entire message" link. Inlined CSS and base64 images both count toward that, so watch it as you add sections.
Safe to customise. Section order, imagery and the number of stories. Newsletters are the one format readers scan rather than read, so the running order matters more than the copy inside any single block.
Leave alone. The single-column fallback below the media query. Outlook on Windows ignores the query entirely and renders whatever the table structure says, so a layout that only works inside the breakpoint collapses there.
Modified it? Check your version against the same 21 clients. The score above is computed from this file, so it moves when the file does.
Scores are computed by the Emailens engine from per-client support data derived from caniemail.com (MIT), analysed against 21 clients and last verified .
Test your email in Gmail, Outlook and Apple Mail
Preview rendering, catch CSS issues, and see what Outlook does to your VML. Free, no account. All 21 clients with one.
Try Emailens Free