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:

1. Country code (2 letters) — e.g., DE for Germany
2. Check digits (2 digits) — calculated using MOD 97
3. 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:

1. Moving the country code and check digits to the end
2. Converting letters to numbers (A=10, B=11, etc.)
3. Computing the remainder when divided by 97
4. Subtracting from 98

The Solution: Random IBAN Generator

I built randomiban.co to solve this exact problem. It generates checksum-valid IBANs for 70+ countries.

Features:

• ✅ Valid check digits (MOD 97 algorithm)
• ✅ Correct country-specific format and length
• ✅ Bulk generation (up to 100 at once)
• ✅ Copy-to-clipboard functionality
• ✅ No signup required, completely free

Supported Countries Include:

• 🇩🇪 Germany (DE) — 22 characters
• 🇬🇧 United Kingdom (GB) — 22 characters
• 🇫🇷 France (FR) — 27 characters
• 🇪🇸 Spain (ES) — 24 characters
• 🇮🇹 Italy (IT) — 27 characters
• 🇳🇱 Netherlands (NL) — 18 characters
• And 60+ more...

Use Cases

1. Unit Testing

// Instead of hardcoding IBANs that might be real
const testIban = 'DE89370400440532013000';

// Generate fresh test IBANs from randomiban.co
// Valid format, zero risk

2. QA Environment Seeding

Populate your staging database with realistic but fake IBANs. Your QA team can test payment flows without any risk of touching real accounts.

3. Demo Environments

Show clients a working payment form with realistic data. No awkward "this is a fake number" explanations needed.

4. Documentation & Tutorials

Include valid example IBANs in your API documentation. They'll pass any validation library your users throw at them.

Also Useful

If you work with other types of test data:

• randomimei.com — Test IMEI numbers for mobile apps
• namso.io — Test credit card numbers
• randommac.com — Test MAC addresses

All free, no signup, built for developers.

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What test data generators do you use in your workflow? Drop a comment below! 👇