Limnu is an online whiteboard for drawing and sketching together on a canvas that is effectively unlimited. It runs in the browser and as an iOS app, and people can start drawing without an account. Boards can be shared with others, who follow changes live, and a "Leading" mode keeps all viewers on the same part of the board. According to the vendor, it is aimed at teams, tutors, teachers and schools, among others. Team plans add administrator controls, such as restricting sharing to the organisation, and an educator plan exists.
Limnu is a US company; its privacy policy gives a postal address in Salt Lake City, Utah. The service therefore falls under US jurisdiction, including the CLOUD Act. The privacy policy does not say where boards are stored and names no hosting provider; it only refers to hosting providers in general and to Google Analytics. No self-hosting option is documented. A European organisation should ask the vendor about data location and processing terms before placing sensitive material on its boards.