Free tools

Free email tools for newsletter teams.

Check your sending domain, see your email in real inboxes and catch bad addresses before they reach your list. Free, no signup, and we don’t keep what you check.

Preflight check

SPF, DKIM and DMARC, plus Gmail’s clip

Check a sending domain’s authentication records, or paste an email to catch bounce risk, broken links, hard-to-read copy and Gmail’s ~102KB cut-off.

Open Preflight

Inbox preview

See it in real Gmail and Outlook inboxes

Paste your HTML and we photograph it in real Gmail and Outlook.com web inboxes, on a desktop screen and at phone width, and tell you if Gmail clipped it.

Open Inbox preview

Ghost Finder

Is this address real, or a ghost?

Check one address before it goes on your list: will it bounce, is it a typo, a throwaway inbox or a role address like info@?

Open Ghost Finder

In Letterhead, these checks run on every issue.

Every issue gets a content check before it goes out: bounce risk, links that won’t work, readability, and email weight with what’s making it heavy. And every newsletter sorts its readers into engagement groups, Ghosts included, so you can size them before you send.

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Get new tools first.

The Letterhead Brief: what’s working in newsletters, plus every free tool we ship. One email a week.