There's https://www.qgis.org/en/site/ https://www.qgis.org/en/site/ but when I've worked with web based projects we've used Django and made a custom UI for it.

There's https://www.qgis.org/en/site/ https://www.qgis.org/en/site/ but when I've worked with web based projects we've used Django and made a custom UI for it. It depends on what type of data you want to display though, for us it was map data so we just used https://leafletjs.com/ https://leafletjs.com/