An isochrone map is one of the best tools for weekend get-aways, job hunting, and finding a home location.
OpenStreetMap[1]! Add it to your site, it will be great hit, in my opinion.
I long for a map experience that's more like a SQL query than a catalog, and Zillow's filtering leaves a lot to be desired.
The results are very different, eg chronotrains-eu.vercel.app claims that Wittenberge is within an hour of Berlin Hauptbahnhof, but GeoApify won't take you further than Nauen. Possibly chronotrains-eu is showing a best-case travel time while GeoApify is attempting to calculate realtime travel using the current day's schedules?
I doubt the main OSM site would ever host an isochrone demo, as it's more of a reference implementation of very basic map and routing features that OSM data enables. Notably, the routing demos there do not (yet) include any kind of transit mode.
Though on geoapify you select a a street address rather than the train stop. So maybe they add a few minutes buffer for walking to the station.
I almost orgasmed reading "isochrone maps". I wasn't aware of the "concept" but it's one of those things you go "of course it is".