With news this week of the messaging app being used to discuss war plans, we get you up to speed on what Signal should be used for—and what it shouldn’t.

Signal has estimated 40-70 million monthly users - making it pretty tiny compared to the biggest messaging services, WhatsApp and Messenger, which count their customers in the billions. Where it does lead the way though is in security. At the core of that is end-to-end encryption (E2EE).

Top Trump administration officials used messaging app Signal to share war plans and mistakenly included a journalist in the encrypted chat, spurring calls by Democratic lawmakers for a congressional investigation into the security breach.