The Assistive Technology Service Provider Interface (AT-SPI) is a platform-independent framework for two-way communication between assistive technologies (AT) and applications.
It is the de-facto standard for accessing free and open desktops such as Linux or OpenBSD
In this architecture, the client and the server must communicate with each other, usually using the platform’s IPC technology.
In the case of GNOME, there are two different APIs, one for the client-side (AT-SPI) and another for the server-side (Accessibility Toolkit (ATK))
The AT-SPI specification itself was related to CORBA as defined in CORBA IDL.