Pages are written in Markdown files that are assembled by Jekyll using the kramdown parsing engine. I edit the code on one of many computers or servers, which are synced through git distributed version controlling (including hosting by GitHub) ultimately to my web server. The rendered result is hosted on general cloud computing at AWS.
Small-scale map data are generated with QGIS and exported to GeoJSON, while larger-scale map data are wrangled with Python and GDAL, then tiled with tippecanoe. Base data for the slippy maps originates from OpenStreetMap with some hosting of tiles by Mapbox.