API Developers required for ArcGIS Enterprise Hosted Data, Services and Layers

We are looking for an API developer, who can develop a token-based Authentication API to deliver ArcGIS Maps, Data and Services to our users, who may deploy such API keys or tokens in ArcGIS, QGIS or any other application. We want to monitor the usage of such API so that it can be controlled as well as monetize in slabs (load basis).