Free • No Signup Required

Preview Your Emails in Gmail, Outlook & Mobile

Paste your HTML code or upload an HTML file directly — see exactly how it renders across every major email client. Catch issues before your subscribers do.

ShiftMailer is free to use — no credit card required!

Try It FreeSee How It Works
Gmail
Outlook
Mobile
Used by marketers & developers
No signup • No credit card
100% client-side • Your data stays private

Email Preview Tool

Paste your HTML or upload an .html file on the left, preview across clients on the right. Compatibility scores and issue detection update in real time.

HTML Editor96 lines
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94

Overall

Excellent

92
Gmail

Excellent

89
Outlook

Good

100
Mobile

Excellent

Gmail Web

<style> tags detected — Gmail strips all <style> blocks. Use inline styles instead.

Gmail

border-radius detected — Outlook ignores border-radius. Buttons/shapes will appear square.

Outlook

max-width detected — Outlook ignores max-width. Use a fixed width attribute on tables instead.

Outlook

Everything You Need to Ship Better Emails

Catch rendering issues across email clients before they reach your subscribers.

Gmail & Outlook Simulation

See how Gmail strips <style> tags and how Outlook ignores flexbox, border-radius, and modern CSS.

Mobile Preview

Preview your email in a 375px viewport — exactly how it appears on an iPhone.

Instant Issue Detection

Get real-time compatibility warnings for flexbox, CSS Grid, missing alt tags, and unsupported properties.

No Signup Required

Start testing immediately. No account, no credit card, no tracking. Your HTML stays in your browser.

How It Works

Three simple steps to perfect email rendering.

1

Paste or Upload Your HTML Email

Drop your raw HTML into the editor or upload an .html file directly. We load a sample template by default so you can try it instantly.

2

Preview Across Clients

Switch between Gmail, Outlook, and Mobile tabs. Each applies real client-specific rendering rules.

3

Fix Issues Instantly

Review detected issues, click "Fix HTML" to inline styles automatically, and re-check your score.

Why Email Rendering Breaks — and How to Fix It

Every email preview tool exists because email clients don't render HTML the same way browsers do. Gmail strips all <style> blocks from the <head>, forcing you to use inline styles. Outlook uses Microsoft Word's rendering engine — which means it ignores flexbox, CSS Grid, border-radius, max-width, and dozens of modern CSS properties.

If you've ever sent a beautifully designed email only to find it completely broken in Outlook email rendering, you're not alone. Nearly 40% of business email is opened in Outlook, and without a way to test email in Gmail and Outlook before sending, broken layouts are inevitable. Mobile adds another layer of complexity — emails must be responsive within a 375px viewport.

That's why we built this free email preview tool. Instead of sending test emails to multiple accounts and checking each one manually, you can paste your HTML here and preview it across Gmail, Outlook, and mobile in seconds. Our email compatibility checker detects common Outlook email rendering issues — like flexbox usage, missing inline styles, and unsupported CSS — and highlights the exact lines in your code that cause problems.

Whether you're a developer building email templates from scratch, a marketer using a drag-and-drop builder, or a founder shipping product update emails — this tool helps you catch issues before your subscribers see them.

Start Testing Your Email Now

Paste your HTML, upload a file, preview across clients, fix issues — all in your browser. No signup, no limits, completely free.

Try Email Preview ToolExplore All Tools

Frequently Asked Questions

What does this email preview tool do?

It simulates how your HTML email renders in Gmail, Outlook, and on mobile devices. It also detects compatibility issues and gives you a compatibility score.

Is this tool really free?

Yes — completely free, no signup required. Your HTML is processed entirely in your browser; nothing is sent to a server.

How accurate is the Gmail/Outlook simulation?

We apply the same CSS stripping rules each client uses — removing <style> blocks for Gmail, stripping flexbox/grid/border-radius for Outlook. It's a close approximation, not pixel-perfect, but catches the most common rendering issues.

What does the "Fix HTML" button do?

It automatically inlines your <style> rules onto matching elements, removes external stylesheet links, adds missing viewport meta tags, and adds alt="" to images that lack it.

Can I use this to test emails from Mailchimp or other builders?

Absolutely. Export your email as HTML from any builder, paste it here or upload the .html file directly, and preview it across clients.

Free Email Preview Tool – Test HTML Email Rendering

Use our free email preview tool to test how your HTML emails render in Gmail, Outlook, and mobile devices. Detect email compatibility issues including flexbox usage, missing inline styles, and Outlook email rendering problems. This html email tester and email client preview tool works instantly in your browser with no signup required. A free litmus alternative for developers and marketers who need to test email rendering online.