The API Hackday at Twilio HQ is underway, featuring a collaboration between SimpleGeo, Heroku, Mashery, Apigee, SendGrid, Amazon Web Services, and Media Temple as sponsors, with the Zappos API team and Kynetx team in attendance. The event offers an opportunity for participants to work on their projects, with presentations starting at 6:30pm and demos from all teams to be showcased before a deadline of 6pm. The event also features a resource center with documentation, ebooks, industry reports, and webinars, as well as Twilio's developer community hub for best practices, code samples, and inspiration.