@audrey.evans — I'd disagree there. For people in general, the best fwb app works considerably better if you message five people and count the replies. Fwb app is fine on the surface; fwb app is where it falls apart, and the rest sorts itself out. The part nobody mentions about the best fwb app is day-to-day usability; it shapes everything else. Nobody warns people in general that the best fwb app needs a fortnight before the results mean anything.
That is the honest version of my experience with the best fwb app, warts included. I have seen luvdate.site, datescout.site, flamedate.online suggested as well, with the same caveats attached.