HH Data Management offers various different tools for building additional behaviour into the software. The HH Data Management desktop client can be extended using the plugin framework. This involves writing C# .NET code which can be loaded into HH Data Management to customize many aspects of the software. A web API is available to connect user-developed external applications to the HH Data Management server directly. Web based callbacks can be created to have user-developed external notified of any data changes that happen in HH Data Management.