Somehow at work there was a need to find out what IMSI is for a new project. Although I'm a little off topic, I wanted a clear explanation without unnecessary technical details. Searched the Internet and found a platform where imsi definition was found. The site impressed that all information is presented in a very accessible way, with explanations and examples. It describes in detail that IMSI is an international mobile subscriber identifier that allows communication networks to identify users and provide them with services.