Email Subject A/B Tester — free online
You wrote an email and now you're stuck on the subject line. Too long? Too short? Will it land in spam? It's easy to second-guess yourself and never hit send. We added a free tool that helps you decide — Email Subject A/B Tester — right in your browser.
What it does
Paste your subject line, generate a few variants, and look at them side by side. For each one it shows the length, the word count, flags any spam-trigger words, and tells you whether you're using emoji. So you can pick the version that reads best instead of guessing.
Nothing leaves your device
It all runs inside your browser. Your subject lines aren't uploaded, sent anywhere, or saved on a server. When you close the page, nothing stays behind.
How to use it
- Open Email Subject A/B Tester and paste your subject line.
- Generate the variants and compare them side by side.
- Pick the one with the best length, no spam flags, and the emoji you want — then copy it into your email.
It's free with no limit. There are more small tools on the Apps page.