Blog

Guides and references for developers who validate data.

How to Validate International Phone Numbers in JavaScript (2026)

4 approaches from simple regex to API-based validation, covering 30+ countries with working code examples and a comparison table.

JavaScript Tutorial 9 min read

Luhn Algorithm Explained: Credit Card Validation in JavaScript

Step-by-step walkthrough of the Luhn checksum, brand detection (Visa, MC, Amex), and a complete 15-line validator.

JavaScript Payments 8 min read

IBAN Validation: Complete Developer Guide (2026)

How the MOD-97 checksum works, country-specific lengths for 45+ countries, bank code extraction, and test IBANs.

Finance Guide 10 min read