A/B test subject lines and content

Split tests send variants to a small sample first, pick the winner by your chosen metric, then send the winner to the rest.

1. 1
   On a new campaign, toggle A/B test

   Choose what to vary: subject line, preview text, or full content.
2. 2
   Set sample size and winner metric

   Usually 20% of list, measured on opens (for subject tests) or clicks (for content tests).
3. 3
   Set the test duration

   4-24 hours. Shorter for large lists, longer for small.
4. 4
   Launch

   After the window, the winner auto-sends to the remaining 80%.