**Background: ** Before we build out a full-fledged Event Invitation tool, we want to develop a prototype for Event Invitations that is smaller in scope and in technical difficulty. This way, we can still generate an Invitation List for organizers based on their campaign event worklists, but the Campaigns team will provide more hands-on support to organizers who want to use the Invitation List rather than the support being made available through a user interface. The goal is to build a basic prototype that can be used for testing the impact of an Event Invitation tool, so we can decide if a) Event Invitations can increase event registrations and therefore campaign contributions for organizers who use the tool, and b) if we do or do not want to continue investing in building an Event Invitation tool based on the findings of the prototype experiment.