OBEX

Obex, or OBEX, stands for Object Exchange and refers to a simple, binary object exchange protocol designed for inter-device communication. It was originally developed by IBM and later standardized in the IrDA protocol suite to enable portable data transfer across infrared links and, later, Bluetooth. OBEX is transport-agnostic and defines a compact request/response model that can carry arbitrary binary objects, along with rich metadata in a small header format.

The protocol operates as a packet-based exchange. Each transaction begins with a connect sequence, followed by operations such as Put, Get, or SetPath to place, retrieve, or navigate object namespaces. Headers carry object metadata, including the object name, MIME type, length, and time stamps. OBEX is designed to be lightweight and easy to implement, making it practical for constrained devices.

In the Bluetooth world, OBEX is used by profiles such as Object Push Profile (OPP) for sending files or contact cards, and File Transfer Profile (FTP) for accessing a remote file system. It has also been widely used in IrDA-based devices and in other transport layers. The protocol enables common tasks like transferring images, vCard, vCalendar, and other binary data between mobile phones, computers, and peripherals.

OBEX has several versions and has influenced later lightweight data-exchange schemes. While the protocol itself is transport-neutral, actual security and user consent depend on the underlying transport and profile settings. See also IrDA, Bluetooth, OBEX FTP, and OBEX OPP.