A/B Testing

A/B Testing is an experiment in which two versions of a product or feature (A and B) are compared to see which performs better in terms of specific metrics, such as conversions, engagement, or usability. A/B testing allows designers and product teams to make data-driven decisions by directly measuring the impact of design changes.

For founders and PMs, A/B testing removes guesswork from decisions about copy, layout, onboarding flows, and pricing pages. Instead of debating opinions in a meeting, you let real user behavior tell you what works — which is especially valuable when you have limited runway and every conversion matters. Even small improvements to a signup or checkout flow can compound significantly over time.

Slack runs continuous A/B tests on their onboarding emails — testing subject lines, timing, and CTAs — to maximize the percentage of new signups who reach their first "aha moment" of sending a message in a channel.