From your Shopify admin, open Address Ninja and click ZIP / Postal Code Format Validation. Search and add the countries where you want to enforce proper ZIP / postal code formatting. Click Activate. Address Ninja will automatically validate that customers enter ZIP / postal codes in the correct format for their selected country (like 12345 for USA, K1A 0A6 for Canada, or SW1A 1AA for UK). You can customize the error message shown when customers enter an incorrectly formatted ZIP / postal code.
Use cases: Prevent shipping issues caused by malformed ZIP / postal codes and ensure addresses meet postal service requirements for each country.