Stream Overlay Chat
A Windows window, transparent and always on top, that shows Twitch chat while you play in borderless windowed mode. With a shortcut the mouse passes straight through it and your clicks reach the game. The installer weighs about 3 MB.
How it works
It is a frameless Tauri 2 window with a transparent background that stays above everything else. The core is written in Rust and the interface is plain HTML and JavaScript with no framework, drawn in the WebView2 that Windows already ships. That is why the installer is so small.
Chat arrives over Twitch IRC on an encrypted WebSocket in anonymous mode, so reading needs no account. Rust parses each message, adds its badges and swaps words for Twitch, 7TV, BetterTTV or FrankerFaceZ emotes, which are downloaded on connect and kept in memory.
To let clicks reach the game, the app changes the window's extended styles through the Win32 API and turns on WS_EX_TRANSPARENT, so Windows stops handing it the mouse. The Ctrl+Space shortcut is registered as a global hotkey on its own thread, so it works while the game has focus.
Subscriber badges need a one-time sign-in with Twitch's device code flow, without typing a password into the app.