Appoint.ly is described as 'No back-and-forth emails, no double booking and only a few seconds to schedule an appointment with you. It's idea is simple: you create your calendar, set your availability and then share it with our clients or co-workers, who can easily schedule an appointment' and is a appointment scheduler in the office & productivity category. There are more than 100 alternatives to Appoint.ly, not only websites but also apps for a variety of platforms, including SaaS, iPhone, Android and Windows apps. The best Appoint.ly alternative is Thunderbird Appointment, which is both free and Open Source. Other great sites and apps similar to Appoint.ly are Cal.com, Doodle, Calendly and TidyCal.