The SXSW Developer Contest is an annual event where developers are encouraged to build a must-have app for the conference using Twilio API as a foundation. The contest aims to promote innovation, creativity, and problem-solving among developers. Winners receive prizes such as VIP access to Twilio events, a SXSW Interactive Badge, and exclusive swag from Twilio. To participate, developers must submit their app by February 20th, use the Twilio API, and provide a video or trailer showcasing their work. The contest is part of Twilio's efforts to foster a community of developers who can build communications and digital engagement experiences.