Email subject line A/B test
Subject lines decide whether your email gets opened or buried. Generate distinct angles that test curiosity against urgency, personalization against brevity — then measure open rates in the real world.
Why test this
A 5% lift in open rate compounds across every campaign you send. Testing subject lines is the highest-leverage experiment most marketers never run properly.
The problem isn't writing one good subject line. It's writing five genuinely different ones that test different emotional triggers — and knowing which trigger won.
Template fields
| Field | Max length |
|---|---|
| Subject line | 60 chars |
| Preview text | 90 chars |
How it works
- Describe — Tell Xaiku about the email campaign. Who's receiving it, what's the goal, what tone fits your audience.
- Generate — Get subject line variants that test different hooks: curiosity, urgency, personalization, direct benefit.
- Refine — See the emotional breakdown of each subject line. Swap phrases, adjust tone with voice controls.
- Ship & Measure — Send each variant to a segment. Track open rates and click-throughs to find the winner.
Start this experimentFree to start. No credit card required.