Custom data is a specific customer data that you enter in Custom Data Maintenance when defining product configuration data or data for each specific unit of product being produced (see Custom Data Maintenance). Data fields created in this activity are located on the Custom Data tab page of the respective maintenance activity. Custom data can be set at the global site, then passed to each site created off that installation.

The ability to define customer specific data allows the application to be extended without customization. These custom fields are key to support integration to SAP ERP or other external systems.