Email Subject Line A/B Tester
Paste your subject line, generate variants, and compare them side by side — length, word count, spam-word flags, and emoji use checked for each. Pick the strongest before you hit send.
No variants yet — enter a subject and click Generate.
Runs entirely in your browser. Nothing is uploaded or stored.
How it works
STEP 1
Enter your subject
Type or paste a base subject line and choose how many variants to generate.
STEP 2
Compare the variants
Each variant shows its length, word count, spam-word flags, and emoji detection at a glance.
STEP 3
Pick the winner
Star the strongest variant and copy it ready to use in your email campaign.