What Is SIM Toolkit App on Android? (STK Explained)
A SIM Toolkit (STK) app on Android is the built-in SIM menu that lets your carrier SIM run interactive services like SIM-based menus, USSD-style actions, and operator-specific messages. In plain terms, it’s not something you install—it’s software on the SIM that can display screens and trigger actions through your phone. You’ll know exactly what STK...