The subject line that actually gets opened.
A/B test up to 4 AI-written subject line variants per campaign. MoreMail tracks opens in real time and automatically sends the winner to the rest of your list — no manual intervention needed.
See it in action
One original subject line → four AI variants, each optimised for a different trigger.
Your original
"Our new feature is here"
How it works
Fully automated from variant creation to winner selection.
AI generates up to 4 variants
Based on your original subject line, the AI produces variations using different angles: curiosity, urgency, social proof, and benefit-led. Each under 50 characters for mobile.
Recipients split round-robin
Your list is divided equally across variants. Variant A goes to the first quarter, Variant B to the second — statistically clean distribution, no cherry-picking.
MoreMail tracks opens in real time
As recipients open, the dashboard updates live. You can see which variant is pulling ahead within the first few hours of sending.
Winner runs to remaining sends
You choose a threshold (e.g. 4 hours or 20% of list opened). Once hit, the winning subject line automatically sends to everyone who hasn't received an email yet.
What the AI optimises for
Each variant targets a different psychological trigger.
Curiosity gap
Withholds just enough information to make opening feel necessary. High performer for product updates.
Benefit clarity
States the exact value upfront. Works best for audiences who are already warm and want to know "what's in it for me."
Urgency / scarcity
Time-pressure or limited availability. Use sparingly — effective only when the deadline is genuine.
Social proof
Numbers, names, or peer activity as the hook. Effective with cold lists or re-engagement campaigns.
Stop guessing. Start testing.
MoreMail finds the subject line your subscribers actually want to open. Free to start.