ATSPI meaning in Computing ?

Assistive Technology Service Provider Interface (AT-SPI) is a platform-neutral framework for providing bi-directional communication between assistive technologies (AT) and applications. It is the de facto standard for providing accessibility to free and open desktops, like Linux or OpenBSD, led by the GNOME Project.

One common nomenclature to explain an accessibility framework is a usual client-server architecture. In that way, Assistive Technologies (ATs) like screen readers, would be the clients of that framework, and computer applications would be the server. In this architecture, client and server need to communicate with each other, usually using the IPC technology of the platform. Ideally the accessibility framework exposes this to the client and server in a transparent way.

Usually the API for both client-side and server-side applications are the same, and the accessibility framework provides a client-side and a server-side implementation of that API. In the case of GNOME, there are two different APIs, one for the client-side (AT-SPI) and a different one for the server-side (Accessibility Toolkit (ATK)) due to historical reasons related to the underlying technologies.