What apps or websites do you use to find campspots?

In the US I start off with FreeCampsites and iOverlander to find general areas, then explore further down crappier roads to get away from the weekenders. :-)

Here is one approach: https://thedyrt.com/magazine/gear/free-camping-pro-map-layers-overview/

we use pitchup.com a lot, will have to have your site as well