HomeKitADK is Apple’s Accessory Development Kit for building HomeKit-compatible accessories in C, from tiny embedded devices to full POSIX systems. It implements the HomeKit Accessory Protocol (HAP) end-to-end, including pairing, authentication, encryption, and accessory/characteristic modeling so you can expose services like lights, locks, sensors, outlets, and bridges. The SDK factors the stack into clear layers—core protocol, transport, and platform shims—so vendors can port it to their MCU/RTOS or Linux/macOS targets with minimal changes. ...