The PI Application Programming Interface (PI API) is intended to provide a common programmatic interface to PI information from the Point Database, the Archive, and PI Tables, as well as providing utilities for data collection interfaces and user application development. The PI API library has ANSI C functions so that code written with the PI API is portable across multiple hardware and software environments.

Support for buffering or caching data across network and maintenance events that interrupt communication are built into the PI API software so that data sent to a PI Server will arrive without the program requiring complicated recovery logic. Buffering in the PI API provides PI Server Collective (HA) support for data writing, but no other functionality in the PI API supports HA (reading data or point database information).

Enabling Operational Intelligence