Email template tester

Check your email HTML before sending: size, missing alt text, links and common markup flags. No test sends or native-client rendering.

Free · No signup · Runs in your browser

Template / inputhtmlfig.

Paste your HTML email

Template / reportchecksfig.

100/ 100

HTML checks

Heuristic score only. No native-client rendering, test send or inbox prediction.

Passing

HTML is below the 100 KiB review threshold (0.5 KiB)
Text content present; review image balance in your client
Unsubscribe text found — verify the actual link and opt-out handling
Inline style attributes detected; client support still needs testing

What the checks cover

Review the markup before testing the message.

Inspect HTML size

The checker flags HTML above its conservative 100 KiB threshold. Final message size can change when your sender adds tracking or other markup.

Check images and text

Find missing alt attributes and image-heavy, text-light markup. Review the actual content and accessibility before sending.

Review CSS and links

Flag style blocks without inline styles, high link counts and missing unsubscribe text. These are review prompts, not a rendering test.

FAQ6 entries

Email template tester questions.

Talk through your workflow with our team.

Talk to sales

It checks HTML byte size, image count, missing alt attributes, visible-text length, link count, unsubscribe text, basic CSS patterns and selected words. The score summarizes those heuristics; it does not predict inbox placement.

No. It does not run native email clients, inspect screenshots or send a test email. Preview and test your final message in the clients your recipients use, including the markup added by your sending platform.

Paste this illustrative HTML: <img src="https://example.com/logo.png"><p>Hello</p>. The report flags a missing alt attribute, an image with little text and no unsubscribe text. Those findings describe the markup; they are not proof the email will enter spam.

No. The checker looks for the word unsubscribe in the markup. It does not confirm a working link, one-click unsubscribe headers or suppression handling. Test the actual opt-out workflow separately.

No. Client support varies by CSS property and layout. The checker only flags a basic pattern: a style block without any inline style attributes. It cannot confirm that every element will render correctly.

The HTML checks run in your browser. You do not need to send a real message or paste mailbox credentials to use this tool.