OpenBinder is a system for inter-process communication.^[1] It was developed at Be Inc. and then Palm, Inc.^[2] and was the basis for the Binder framework^[3] now used in the Android operating system developed by Google.^[4]

OpenBinder allows processes to present interfaces which may be called by other threads. Each process maintains a thread pool which may be used to service such requests. OpenBinder takes care of reference counting, recursion back into the original thread, and the inter-process communication itself. On the Linux version of OpenBinder, the communication is achieved using ioctls on a given file descriptor, communicating with a kernel driver.

The kernel-side component of the Linux version of OpenBinder was merged into the Linux kernel mainline in kernel version 3.19, which was released on February 8, 2015.^[5]