The Retina Tiles API can be used in QGIS to get a high resolution basemap with OpenStreetMap retina tiles.
Quick Start Guide:
Register at RapidAPI (it’s free!)
Subscribe to a plan at https://rapidapi.com/MapTilesApi/api/retina-tiles/pricing/
Fetch your RapidAPI key (you’ll find it on https://rapidapi.com/MapTilesApi/api/retina-tiles/ if you are signed in)
Replace YOUR-RAPIDAPI-KEY with your api key (obtained in 3.) in the following XYZ connection example in QGIS
In QGIS open the “Add XYZ Connection” option in the QGIS browser (through right click on XYZ tiles->New Connection) and enter the following:
Min Zoom Level: 0
Max Zoom Level: 19 (the Retina Tiles API also supports a max zoom level of 20, but this zoom level is in beta mode and is not guaranteed)
Tile Resolution: High (512x512 / 192 DPI)
Please note: For a perfect basemap experience, look out for the scale of your map in QGIS (the scale can be changed in the bottom menu). To prevent a blurry map display, don’t use an odd scale but rather values like e.g. 1:4000, 1:2000, 1:1000 or (with max zoom level 20) 1:500.