Gmail vs Outlook Rendering Quirks
Gmail strips style blocks; Outlook desktop uses Word rendering. Both behaviors require different mitigations.
| Area | Gmail | Outlook |
|---|---|---|
| <style> blocks | Stripped on forward. Use inline styles. | Honored in Outlook 365/Web. Stripped in Outlook desktop 2016+ (Word renderer). |
| Background images | Supported | Supported on Web only. Outlook desktop needs VML fallback (Microsoft-specific markup). |
| Web fonts | Supported only when using fallback @import + <link> | Outlook desktop NEVER supports web fonts. Always system-font fallback. |
| CSS flexbox/grid | Supported | Outlook desktop: not supported. Use tables for layout. |
| Dark mode | Auto-invert on Android; opt-in on iOS | Auto-invert in Outlook desktop dark mode. Color overrides via mso-line-height-rule. |
| Tracking pixels | Proxied through Google's image cache → IP geolocation lies | Direct fetch from your tracking host. Real IP. |
| Hyperlink colors | Honors inline color | Outlook desktop adds default blue underline; suppress with mso-style-priority and !important |
You know the rule. See where you sit against it.
Reference pages tell you the benchmark. Outsolvi tells you whether your team is above or below it. per-rep, per-deal, per-week. and which behavior changes move the number. From $7/user/mo yearly.
See your numberPer-property comparison of CSS support, image handling, font fallback, dark-mode behavior, hyperlink coloring, and table layout.
Before sending an HTML email to a mixed-client audience. After a 'looked great in Gmail' / 'broken in Outlook' bug report.
FAQ
Why does my email look right in Gmail and break in Outlook?+
Outlook desktop renders HTML with the Word engine, so flexbox, grid, and web fonts don't apply and layout falls back to tables. Gmail has its own habit of stripping style blocks on forward, which is why inline styles are the safer default.
Does this tool preview my HTML in both clients?+
No. It's a side-by-side reference of how the two clients handle style blocks, background images, web fonts, flexbox and grid, dark mode, tracking pixels, and link colors. Actual previews need a test send or a rendering service.
Why is the tracking pixel row different between the two?+
Gmail proxies images through Google's image cache, so the IP you record is Google's and not the reader's. Outlook fetches from your tracking host directly, so the IP is closer to the real one.
Keep going
Articles, glossary entries, and other tools on the same topic.
Nate built Outsolvi after watching every email-tracking tool he had ever used lie to him about opens. Outsolvi runs Tier 1 to 5 confidence scoring on every open, native in Outlook and Gmail, so the number on the dashboard is one a rep can actually act on.
We update these pages when the underlying mechanics change. new mailbox-provider rules, new tracker behavior, new measurement gaps. The dates above are real revisions, not auto-touches.