EventBrite Online RSVP - EventBrite Online RSVP is a cost-effective event management software that provides services to help businesses organize, invite people together for an event, and sell tickets.
Pingg - Pingg is an online e-cards and invitation maker and invitation sending platform.
Rsvpify Virtual Events - Rsvpify Virtual Events is an event management tool that provides you various functionalities ranging from setting up the entire event to selling the tickets online to the targeted audience.
Anyvite - Anyvite provides an efficient way to create invitations, with a range of tools necessary to organize and communicate with attendees throughout the event lifecycle
EventCreate Online RSVP - EventCreate Online RSVP is a tool for collecting RSVPs online.
Zoji - As claimed by the developers of this Zoji, it caters online tools to aid you plan activities off-line.