The core data types of the VisionAppster runtime are defined in C. Other programming language APIs build on top them. The C tool API lets you to implement new analysis tools in C. The data link API provides a comprehensive interface for implementing drivers that connect to I/O devices, PCLs, databases etc. If you only need simple digital I/O the remote I/O protocol is the easiest choice. Its C API provides a simple way of building custom I/O servers.