Slack Events API - Subscribe to events in Slack via HTTP
Eventbrite - Discover Great Events or Create Your Own & Sell Tickets
B12 Bookings - Bookings scheduling software that integrates with your site
Cvent - Cvent's event management software provides event planners with a complete solution to increase event attendance and decrease event costs.
Guestboard - Lead powerfully-organized group events with Guestboard – a modular event platform that gives groups of 10-1000+ people a central space to coordinate, build excitement, and save money. No more crazy email threads. No more massive group texts.
Ticket Tailor - Ticket Tailor is an easy-to-use event ticketing platform that allows event organizers of all shapes and sizes to sell tickets online.