Split testing is the practice of comparing two versions of an email to see which one performs better, functionally identical to A/B testing, with the two terms used interchangeably across the email marketing industry.
A quick answer to what is split testing worth remembering: same process, different name, there’s no meaningful technical distinction from A/B testing to learn separately.
The Same Practice, Two Names
Split testing vs A/B testing isn’t really a meaningful distinction in modern usage. Both describe splitting a sample of subscribers into two groups, sending each group a different version, subject line, content, send time, and measuring which version wins on a defined metric. Some platforms and some regions favor one term over the other in their documentation, but neither describes a genuinely different process.
Split testing examples cover the same ground A/B testing does:
- Subject line variations, the most common and highest-impact starting point.
- Send time differences, testing whether an earlier or later delivery performs better.
- CTA wording or button color, isolating one visual or copy variable at a time.
Split testing email marketing terminology traces back slightly further historically than A/B testing as a phrase, originating in direct mail and print advertising before email existed, while A/B testing became the more common phrase once digital marketing tools popularized it. Today, the choice between the two terms is almost entirely stylistic.
For the full breakdown, the formula, the process, and what to test first, see our complete A/B Testing guide.
Related terms:
Adflipr’s Automations feature includes Split Path, letting you branch subscribers down different paths to compare what performs better, the same underlying split testing concept applied inside a workflow.
