This report examines the patchwork of online text‑based instant messaging applications preferred by jihadist and far‑right extremist groups, with a focus on charting their technical affordances and their host companies’ stances on user privacy, security and regulation. To this end, the report analyses six online messaging services (BCM, Gab Chat, Hoop Messenger, Riot.im, Rocket.Chat and TamTam) that have been or may be used in conjunction with Telegram by extremist groups.