Twitch uses a machine learning system at account signup to detect and prevent the creation of usernames containing offensive, hateful, or otherwise inappropriate content before accounts are created.

Formally announced February 10, 2022 (effective March 1, 2022) as part of a broader username policy update. Twitch stated the new policy "will help prevent the creation of new offensive usernames when leveraged alongside machine learning at signup." The company described having created a "machine" that flags attempts to create offending usernames. Work on this capability predates the 2022 announcement — a 2020 Tom's Hardware article quoted Twitch confirming "enhanced offensive username detection" was already underway. Existing users with hateful/violent usernames faced indefinite suspension; others were locked until they changed names via a self-serve tool.