How to Generate Valid Test IBAN Numbers for Development

The Problem Every developer who has worked with banking integrations knows the struggle: you need valid IBAN numbers for testing, but using real ones is a terrible idea. Real IBANs can accidentally trigger actual bank transfers in poorly configured staging environments. And generating random strings won't pass IBAN validation (check digits, country-specific formats, etc.). What Makes an IBAN Valid? An IBAN consists of: Country code (2 letters) — e.g., DE for Germany Check digits (2 digits) — calculated using MOD 97 BBAN (Basic Bank Account Number) — varies by country For example, a German IBAN looks like: DE89 3704 0044 0532 0130 00 DE = Germany 89 = check digits 370400440532013000 = BBAN (bank code + account number) The check digits are calculated by: Moving the country code and check digits to the end Converting letters to numbers (A=10, B=11, etc.) Computing the remainder when divided by 97 Subtracting from 98 The Solution: Random IBAN Generator I built randomiban.co to solve this e