Steve Carlton launched Invitd in July 2014 after testing text-message invitations for his daughter’s birthday party. The rate of R.S.V.P.s was so much better than any other method he had used, such as email and Facebook, that he decided others might see value in a text-message-based invitation system. The free Invitd app, available for iOS and Android, has now been used to send nearly one million invitations. Hosts create a custom invitation by entering the name, location, and time of their event and selecting contacts from their address book to receive it. Recipients get a text message addressed to them by name with a link to the event details and R.S.V.P. options; they don’t need to have the app installed to view the invitation. In addition to responding “yes” or “no,” recipients can indicate how many people will attend, and they can add a reminder to their calendar. While the app can handle an unlimited number of invitees, Carlton says he will soon release an update that will add an easier interface for planners who want to use it for large meetings and events.