Statsig is a software product experimentation tool designed to make A/B testing more useful for more companies. The company has announced $43 million in Series B funding in a round led by Sequoia Capital with participation from Madrona Venture Group.

A/B testing is a technique where two variations of a change are shown to two different groups of customers, and whichever one works better (however better is defined) is chosen over the variant that didn’t work as well. It’s a form of market testing made famous by search engines and now in common use across the tech industry.