Post and vote for questions or messages using mobile phones or other internet devices during large lectures, classes, meetups, or conferences: free-of-charge, anonymous, ad-free, easy-to-use.

Huh, neat.

I'm not sure if the source code is openly published, but there's a derivative code-base (Dockerized version) that is. The author of the original website is Prof. Dr. Thorsten Thormählen at Marburg University, where the website is also hosted.

• https://onlinequestions.org
• https://onlineclicker.org