Why postal code boundaries and administrative boundaries differ
A postal code area and a city or county boundary are drawn for entirely different purposes, and they frequently do not line up, which trips up anyone who assumes they should.
Tag
#postal-codes
The case for treating postal code lookups as first class
A postal code endpoint priced and documented like an afterthought will get built like one too. Treating it seriously starts with treating it equally.
Why some countries publish better postal code data than others
Postal code data quality is not random, it tracks closely with how each country's postal authority builds, maintains, and shares its own reference data.
Postal codes deserve more respect than they get
Postal code lookups get treated as a minor utility next to geocoding, but they carry real structure and real regional variation that deserves the same care.
Postal code granularity: the UK versus the US versus everywhere else
A UK postcode can identify a single street or even a handful of buildings. A US ZIP code covers a much larger area. Postal granularity varies enormously by country.