Email TOOL · FREE TO USE

Email HTML Preflight Tester

Find common markup, content and accessibility issues before sending.

Runs on your device · Files stay private

Your email workspace

Email HTMLMerge values as JSON

01 / INPUT

What you’ll need

HTML plus optional merge-field JSON.

02 / METHOD

How it works

Local parsing, sandboxed preview, link inventory, alt checks and plain-text export.

03 / SCOPE

Know the limits

Browser preview only, not actual Gmail/Outlook rendering, live link checks or inbox placement.

GET FROM A QUESTION TO A NEXT STEP

Get a clearer result with Email HTML Preflight Tester

Find common markup, content and accessibility issues before sending. HTML plus optional merge-field JSON. Review the supported scope below before adding a large file or using the result in a campaign.

How to use Email HTML Preflight Tester

Open Email HTML Preflight Tester and inspect its input labels. HTML plus optional merge-field JSON.
Use the synthetic example where available, or choose your own supported file. Set the options deliberately; processing takes place in your browser.
Run the workflow, read any warnings and inspect the output. Download the result only after checking the values or file preview; clear the workspace when finished.

What do the results mean?

Local parsing, sandboxed preview, link inventory, alt checks and plain-text export. Browser preview only, not actual Gmail/Outlook rendering, live link checks or inbox placement.

What to do next

Check a small representative input first. For exported assets, reopen the downloaded file in its intended application before using it in production.

Keep the scope in mind

Browser preview only, not actual Gmail/Outlook rendering, live link checks or inbox placement.

A LITTLE MORE CLARITY

Common questions about Email HTML Preflight Tester

Does Email HTML Preflight Tester save my input?

This workflow uses browser memory. Downloads are saved by your browser, but tool inputs are not submitted to a server or stored by this tool.

What should I do if a result is unavailable?

Check the input format, units and limits. Browser preview only, not actual Gmail/Outlook rendering, live link checks or inbox placement. An unavailable result does not establish that a campaign, document or email address is valid or invalid.