In this article, we introduce the Planet-Box-Extractor API (developed by VAIS) which enables the extraction of bounding boxes of interest from Mercator Web Tiles. The extraction of bounding boxes from the spherical surface of the Earth requires special mathematical treatment which we discuss in the first section of the article. Then, we explore the cartography used by modern web-based map providers. Finally, we illustrate how our API can be used with Planet.com API to retrieve a bounding box around a given location, using the Lacuna - Correct Field Deection Challenge.