An experiment management system for an online visual design system including an experiment creator to receive an experiment specification with source material from an external source and to create an experiment definition based on inspection and analysis of the source material; an experiment integrator to integrate the experiment definition as an experiment into the experiment management system; an experiment configurer to configure a variant and population selection criteria for the experiment and an experiment manager to manage the experiment and at least one other experiment during the execution of the experiment at runtime of the online visual design system according to the variant and population selection.