There is a sentence that reliably buries a good idea: "man müsste mal", someone really ought to. You say it, and then you keep driving.
In my case I really was driving. Another brown tourist sign went past on the autobahn, a castle, a wildlife park, some monastery, and I thought that this ought to be on a map. Not sights in general, but specifically the places that work with children in the back seat.
The conversation in the car at that moment happened to be about entrepreneurship, and about the plain fact that things do not happen by themselves. They happen when somebody makes them happen. A "man müsste mal" never becomes anything. An "I am starting now" sometimes does.
What made it concrete
The idea took its shape from the places we remember fondly. The Wildgehege Hufeisen in the Veldensteiner Forst, where the children saw deer and wild boar close up. The Bärenwald Müritz in Stuer, where bears out of bad captivity get a home worth the name. Stops like these turn a long drive into a small outing. The only hard part is knowing that they exist, and knowing that they are worth the detour once children are involved.
Why I am building the stack myself
There is a second motive, and it is entirely selfish. I had wanted to build something with GIS for years, with real geodata and real maps. My fellow student Stefan showed me with Mapnificent how simple it can be to make something as abstract as reachability visible on a map, and that stuck.
So the routing runs on self-hosted OSRM, the vector tiles come off my own machine, and the catalogue lives in PostGIS. None of that is necessary to put pins on a map. A hosted routing API would be faster to integrate and cheaper to operate at this size. It is necessary if the actual goal is to understand the system you are building, which in this case it is.
Rücksitzhelden is an attempt to turn a "man müsste mal" into a "we started".