A high-level development environment is provided free with Cadcorp SIS Desktop

Cadcorp SIS Desktop includes built-in capabilities for its extension and customisation.  These are based on GisLink technology providing access to the Cadcorp SIS API and can be used to create or modify Add-In applications for Cadcorp SIS Desktop. The high level development environment is identical to that of the ActiveX SDK. It gives the developer granular control over all aspects of their mapping data and interfaces. The development environment can be used to build routines, extend functionality, and customise interfaces and workflows.

Routing Tools Add-in extends the functionality of Cadcorp SIS Desktop at no extra cost

Cadcorp SIS Housing Toolkit