Most online utilities quietly upload what you type, paste, or record before showing a result. CapyToolkit is the opposite: 47 free tools that compute on your device. Test a gamepad for stick drift, measure a mouse polling rate, sweep a speaker from 20 Hz to 20 kHz, decode a JWT, or strip GPS data from a photo, with nothing sent to a server and no account required. Install it from the Microsoft Store or use it in the browser. Worked examples back every tool.