Protomaps is an open-source system for interactive web maps. It has three parts: PMTiles, an open single-file archive format for map tile data; tools and libraries for creating and serving PMTiles; and a basemap of roads, water and labels built from OpenStreetMap data. A map can be deployed as one static file on ordinary cloud storage, without a tile server. The planet basemap can be downloaded, or an area extracted with the command-line tool.
The project is released under BSD and ODbL licences: the reference implementations use BSD 3-Clause, the PMTiles specification is public domain, and the basemap is an ODbL produced work that requires OpenStreetMap attribution. The copyright holder is Protomaps LLC; its public pages do not state where it is located. Because the files can be copied to storage of your choice, including an EU provider or your own servers, an organisation can serve maps without a third-party tile provider.