· Coursera

It offers more than 1000 courses from over 140 universities around the world in numerous fields. The website also has an app to follow your courses wherever you go. All courses are free and available in different languages. You can also get a certificate at the end of the course.

· Udemy

It offers more than 40,000 classes and is used by over 13 million students. Classes in various subjects are available in different prices and some are free. The content varies from visuals, video, and articles.

· Pluralsight

This site is visited by over one million students and offers 6,000 classes taught by more than one thousand lecturers. Classes include information technology, design, and others. Pluralsight also has features such as measuring progress and interactive games in edutainment form.