The Objects API and the Objecttypes API are two components that complement eachother. The Objecttypes API holds the object definitions for objects that can be stored in the Objects API. Together they provide a powerfull way to create and store any kind of object. They are designed line with the Common Ground model and they can be used by other API’s that need to store some object specific data.
Both the Objects API and the Objecttypes API are and only use Open-source.
To get you started, you might find some of these links relevant:
The Objecttypes API aims to standardize various types of objects, on a national level, in an accessible way and without the need to create a whole new API for each (simple) object.
This national Objecttypes API is required for registering objects in local Objects API. Organisations can also run an Objecttypes API locally, to use both national and local definitions of objects.
The Objects API aims to easily store and expose various objects and make them available in standardized format. The Objects API can be used by any organization to manage relevant objects. An organization can also choose to use the Objects API to expose objects to the public, as Open Data.
To define the format of objects, so called object types, organizations can use a national and/or local Objecttypes API.