Data source
Postal data comes from the GeoNames postal dataset, published under the Creative Commons Attribution 4.0 licence: one of the most complete open postal databases in the world. We currently serve 887,146 codes across 95 countries.
How it works
The dataset is refreshed monthly on our own servers and served from a local index, so lookups are instant and never depend on a third-party service at request time. Codes are normalized before matching, so case, spaces and hyphens do not matter.
Accuracy
Open postal data is very good but not authoritative: operators add and retire codes continuously, and coverage varies by country (for the UK, the dataset covers outward codes such as SW1A rather than full unit postcodes). For legally or operationally critical mail, confirm with the national postal operator.
Who is behind this
PostalCodeCheck is built and operated by IPNOVA SYSTEMS LTD, a Cyprus software company that builds free, data-driven utility platforms, including AreaCodeCheck, BankHolidayCheck, SwiftCodeCheck and IPSnapshot.
Contact
Questions, corrections or higher API volume: [email protected]