The IPMon API interface is a RESTful API designed using Node.js that provides a simple way to track and manage IP addresses for geolocation purposes. The API has endpoints for creating, reading, updating, and deleting IP address records, as well as showing all tracked IP addresses. It relies on the RapidAPI service for fetching IP address details from its geolocation API. The API uses a Map object to store IP address data in memory, which is replaced by a real database component in the second part of this post.