A/B testing campaigns
Stop guessing which subject line or design wins — test it. An A/B campaign splits your recipients across variants, measures how each performs, and lets the data decide.
What you'll need
- A campaign audience (list or segment) large enough to split meaningfully
- Two or more ideas to compare — subjects, templates or both
How an A/B campaign works
You create a campaign as an A/B test and add variants. Each variant carries a weight that determines its share of the audience, and each contact is assigned to exactly one variant — the same way every time, so results stay stable and un-skewed.
- Variants — two or more versions to compare.
- Weight — each variant's share of the split (e.g. 50/50, or a small test slice per variant).
- Stable assignment — a contact always lands in the same variant, so a resend won't scramble your test.
What you can vary
- Subject line — the most common test, and often the biggest lever on opens.
- Template — test an entirely different design or layout per variant.
- Or both — give each variant its own subject and template.
Pick the winner
Set which metric decides the winner — opens or clicks — and how long the test runs before that decision. When the window closes, the winning variant is the one that led on your chosen metric.
- 1
Create an A/B campaign
Start a new campaign and choose the A/B type instead of a regular send.
- 2
Add your variants
Add two or more variants, set each one's weight, and give it a subject and/or template.
- 3
Choose the winning metric and window
Pick opens or clicks as the winning metric and set how long the test should run.
Frequently asked questions
What should I test first?
Subject lines — they're the biggest lever on opens and the easiest to compare cleanly. Move on to content once your subjects are dialed in.
How is a contact assigned to a variant?
Deterministically by weight — the same contact always gets the same variant, so results aren't skewed by resends.
How is the winner decided?
By the metric you choose (opens or clicks), measured over the test window you set.
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