Twitch Username and User ID Translator
Simple extension that converts Twitch usernames to user ids, and user ids to usernames. Will notify you if the username or user id is invalid. Version 1.5: Auto detection (thanks GhostZero). Copy link and message added. Success/error messages shown/hidden as appropriate. Version 1.4: Adds support for new Twitch API (Helix), and slight UI changes to make usage easier.