Optimizely is a comprehensive digital experience platform that offers a range of tools for website optimization, including A/B testing, multivariate testing, and personalization. It allows marketers and developers to experiment with different versions of web pages or features to determine which performs best in terms of user engagement and conversion rates. Optimizely's platform is designed to help businesses make data-driven decisions to enhance user experiences, improve website functionality, and increase overall performance of their digital properties.