Confidence.js is a simple JavaScript library that helps you make sense of your A/B test results. It uses the conversion rates of A/B test variants to determine if one of them is likely to perform better. Confidence also lets you know if there is enough data to make the final decision.

Here at Sendwithus, we know how important it is to have enough data to confidently choose a winning variation. If you stop your A/B test before enough data has been collected, the variant you select might not deliver the results you’re expecting. We have worked hard to understand the statistics and math behind A/B testing so you don’t have to.

In our research, we found that most A/B testing resources can really put a person to sleep.

We decided to open-source the library that we use at Sendwithus so that everyone can understand their A/B tests without doing all the complicated math by hand.