The device side of the library: your program is the USB device.

Everything under this section is a task-focused recipe - the smallest code that does something real, lifted verbatim from the runnable programs under examples/. Run one, then import it (USB/IP clients) to see the host's own driver bind.

USB Classes - the ready-made, host-recognised classes: keyboard, serial port, disk, webcam, sound card, media transfer, firmware upgrade, Bluetooth dongle. One reference page per class, and a runnable example for every class but Bluetooth.
Vendor Devices & WebUSB - your own protocol, opened from your code or a browser.
Composite devices - several functions on one device: a disk and its serial console.
Multiple devices - several independent devices from one process, each with its own identity and busid.

New to USB? Read the short USB concepts primer first - it explains the vocabulary (descriptors, endpoints, the SETUP packet, STALL) these recipes use. To drive a device instead of being one, see Host.