Working notes
Articles
The object models behind Swedish registry data, the identifiers that are not keys, and the traps that only surface once the data is in production.
· Company data
Organisationsnummer: format, checksum and company lookup
The 10- and 12-digit forms, what the first digit means, a Luhn check you can paste, and the one-company-many-workplaces trap.
· Property data
Swedish property data: fastighet, byggnad and belägenhetsadress
How the Swedish property register is actually structured — designations, parcels, buildings, addresses, coordinates — and how to walk it over HTTP.
· Platform
Swedish registry API: one key for people, property and companies
Sweden's registers are public, but access to them is not uniform. What a unified API replaces, what it does not, and how a request actually looks.