We just released a very helpfull Magento 2 Module when it comes to REST API projects.
What are the functions of the modul?
The module just logs all REST API Calls of a magento store into a table. It does some enrichment of the data for better filter later. This data is than accessible by a listing in the magneto admin area.
For more information about our magento Rest API Logger Module and where to get it check out
https://www.konvis.de/magento-api-logging-and-monitoring-modul-for-magento-2-onlinestore/