How does auto-detection work?

The browser compares normalized input against supported country and identifier patterns, then runs the relevant Luhn, Mod 11, Mod 97, ISO 7064 or base-36 checksum when one exists.

Is validation sent to a server?

No. Universal validation and generation run locally. No input is stored or uploaded.

Why can a real number be reported invalid?

Local rules cover supported format and checksum conventions, not every authority-specific exception. Check the issuing authority when a production identifier matters.

Tax ID Validator

Auto-detect and validate taxpayer, VAT, EIN and GST identifiers in your browser

For Development & Testing Purposes Only - Synthetic Mock Data

Privacy Notice: This tool runs entirely in your browser. Nothing you generate or enter is sent to any server or stored anywhere.

Options

Standard

Display format

Generate one checksum-valid mock value. Open Bulk for up to 500 records.

US EIN Number Format Testing Guide

Use IRS-compatible EIN campus prefixes and synthetic company metadata in QA fixtures.

ABA Routing Number Generator

Generate 9-digit US ABA routing numbers with weighted Mod-10 checks.

Address Generator

Generate realistic addresses in the correct format for 21 countries — single-line, multi-line, JSON or HTML — plus a postcode validator. Test data only, runs in your browser.

ASCII Text Art Generator

Turn text into large ASCII art banners with multiple figlet fonts

Credit Card Generator

Generate Luhn-valid test credit card numbers for development and QA (not real cards)

Crypto Address Generator

Create testnet-shaped ETH, BTC, SOL and TRON addresses with checksums.

Driver's License Generator

Generate driver's license numbers in the correct format for 21 countries and all 50 US states, plus a format and Luhn validator — test data only, runs in your browser.