Kahoot! is not available as a self-hosted solution but there are a few alternatives for power users and business that want to host a solution on-premise. The best open source Self-Hosted alternative is ClassQuiz. If that doesn't suit you, our users have ranked more than 50 alternatives to Kahoot! and three of them are open source and available as a self-hosted solution so hopefully you can find a suitable replacement. Other interesting open source Self-Hosted alternatives to Kahoot! are Arsnova.click and MARS (Audience Response System).
ClassQuiz is a quiz-application like KAHOOT!, but open-source which is very important if it is a product for educational purposes. You can create quizzes and play them remotely with other people. It is mainly made for teachers, who create a quiz, so students can compete with...
MARS is a client-server Audience Response System dedicated to e.g. teachers, moderators to support their courses to evaluate knowledge, assess opinions or illustrate concepts, or just for fun!
Early stage project, but in heavy development. For know it provides a basic editor for multiple choices questions, easy to take in hand in a matter of minutes.