Can preheader text be A/B tested?

Yes, preheader text (the preview text that appears after the subject line in inbox views) is an excellent A/B testing candidate.

Preheaders influence open decisions because they provide additional context that helps recipients decide whether to engage. Testing them follows the same principles as subject line testing.

Test strategies include:

Complementing versus repeating the subject line. Summary versus teaser approaches. Call-to-action versus benefit statement. Personalized versus generic preview text.

Common mistake: Many senders ignore preheader optimization entirely, leaving it to default to the first line of body copy. This wastes valuable preview real estate.

Measure success through open rates as the primary metric, validated by downstream engagement.

Preheaders are the subject line's partner. Testing both together as a system often produces better results than optimizing either alone.