Wherever a rule follows a border

Most delivery zones are a list of places: these cities, those postcodes, not that district. Draw them from the official boundaries instead of by hand, and check every order against the same polygons.

Sales tax, tourist levies and local fees follow administrative lines, not postcodes. Reverse-geocode a point to every boundary that contains it and apply the rules of each.

Territories are written as lists: “Texas and Oklahoma, plus the Kansas City metro”. Turn that sentence into one polygon, then route every lead by where it is.

Buyers search by neighborhood and city, not by radius. Give listings, search filters and market reports the real boundary polygons.

Routing rules, driver pay and customs paperwork change at borders. Check thousands of GPS points against the right boundaries in one call.

Policies define territory in words: “the Province of Madrid, excluding the municipality of Madrid”. Areas turns that clause into a polygon, or says exactly why it can't.

Taxi tariffs, airport surcharges and scooter permits are defined by city councils in prose. Map the decree once, then answer “which fare applies here?” with a lookup.

Service eligibility, grants and reporting all run on administrative units. Get each unit's polygon, parents and children from one API, with stable ids across datasets.

Rolling events up to regions and drawing choropleths both need the same thing: clean polygons with stable ids. Fetch them from one API, simplified to the zoom you draw at.