A/B testing for subject lines
Let your prospects pick the best subject line.
Split-test subject lines across matched audiences and see which one earns more replies, with significance calculated for you.
Test results
- A, quick question about Q4●3.1% reply
- B, idea for Acme's onboarding▲5.4% reply
- C, Acme and remote teams●2.7% reply
- Confidence●95%
- Winner▲B
What we do
Fair splits
Matched audiences and timing for every variant.
Reply-based winners
Judged on replies, not just opens.
Auto-winner
Send the winner to the rest of the list.
How it works
- 1
Paste or upload
Drop in your email, list or domain. No setup needed.
- 2
Get results
A clear score and line-by-line findings in seconds.
- 3
Improve
Apply suggested fixes and test again.
Get in touch
Leave your email and we will reply within one working day, or write to us at hello@subjectabtest.com.