The available developer kits and developer related documentation can be downloaded here.
API Developer Kit
Application Programming Interface (API) is a developer environment in which you can access internal functions of applications. With the help of this tool you can develop Add-On software to extend Archicad's standard functionalities. Also this tool enables you to create I/O interfaces for converting ArchiCAD files to different formats.
Rendering Developer Kit
PhotoRendering is a method for creating photorealistic images of 3D models. ArchiCAD is prepared to use various PhotoRendering engines for this purpose. This developer kit enables you to extend ArchiCAD's visualizations capabilities by developing PhotoRendering Add-On software.
Open Database Connectivity (ODBC) is a widely accepted interface for database access. It is based on the Call-Level Interface (CLI) specifications from X/Open and ISO/IEC for database APIs and uses Structured Query Language (SQL) as its database access language. The ODBC Driver reads ArchiCAD project files and gives you database access to the content of these files. Using this tool you can extract and further process ArchiCAD project data in other applications.
Library Developer Kit
Libraries contain external files used by ArchiCAD or referred to by construction elements within ArchiCAD. Parts of these are GDL objects programmed using the Geometry Description Language (GDL). This developer kit helps you develop GDL libraries for ArchiCAD for commercial use.