Udacity

Udacity is one of the leading online education provider which teamed up with Google, AT&T and other tech giants for Open Education Alliance (OEA). OEA intends to provide students around the world with a curriculum and skills they need to pursue careers in technology. Its partners include Google, Autodesk, Cloudera, Intuit, 23andMe, Khan Academy and Georgia Tech.

Udacity focuses more on vocational courses for professionals which are project based with personalized support. Currently Udacity is offering more than thirty five courses which are divided into six categories-Data Science,Web development, Software Engineering, Android, Georgia Tech Masters in CS, Non-Tech Classes. Instead of exams, evaluation is based upon project. Udacity’s online courses are rigorous and its projects are built by tech leaders like Google, AT&T, and Intuit, to develop relevant industry skills. After enrollment Udacity offers courseware, coach and project with feedback. It also provides verified certificate  recognized by industry. 

Access to course, video and exercise is free of cost. Without paying any fee, you can also view and manage your progress. But for in class project, project feedback, code reviews, personal guidance from coach, personalized pacing support and verified certificate, you have to pay fee. Students can enroll in one or more courses at any time. The course can be completed at the student's preferred pace.