Credit Card Generator

Generate Luhn-valid credit card numbers with vendor-specific prefixes for testing purposes

The generated numbers have the right length, start with a real issuer identification number of the vendor and pass the Luhn check, so they get through the format validation of payment forms. They do not belong to real accounts and cannot be charged.

The package ships ES module and CommonJS builds with TypeScript declarations and has no runtime dependencies.

Installation

The package is published to GitHub Packages. Point the @jermainee scope to its registry in your project's .npmrc and authenticate with a token that has the read:packages scope:

@jermainee:registry=https://npm.pkg.github.com

npm install --save-dev @jermainee/credit-card-generator

Installing straight from the repository works as well and builds the package on install:

npm install --save-dev github:jermainee/credit-card-generator

Usage

Import the CreditCardGenerator and the CreditCardVendor enum:

import CreditCardGenerator, { CreditCardVendor } from "@jermainee/credit-card-generator";

With CommonJS the generator is the default export:

const { default: CreditCardGenerator, CreditCardVendor } = require("@jermainee/credit-card-generator");

Generating a single credit card number:

const creditCardNumber = CreditCardGenerator.generateSingle(CreditCardVendor.VISA);
// "4716169796495547"

Generating multiple credit card numbers:

const creditCardNumbers = CreditCardGenerator.generateMultiple(CreditCardVendor.MasterCard, 3);

Generating a credit card number using your own preset (see ICreditCardPreset):

import CreditCardGenerator, { type ICreditCardPreset } from "@jermainee/credit-card-generator";

const preset: ICreditCardPreset = { digitCount: 19, prefixes: ["4"] };
const creditCardNumber = CreditCardGenerator.generateWithPreset(preset);

digitCount is the total length of the number including the prefix and the check digit. One of the prefixes is picked at random for every number.

Checking numbers with the Luhn algorithm:

import { calculateLuhnCheckDigit, isLuhnValid } from "@jermainee/credit-card-generator";

isLuhnValid("4111111111111111"); // true
calculateLuhnCheckDigit("411111111111111"); // 1

Invalid input throws instead of producing invalid numbers: unknown vendors throw an Error, counts that are not non-negative integers throw a RangeError and malformed presets throw a TypeError or RangeError.

Supported credit card vendors

Vendor	Digits	Prefixes
VISA	16	4
MasterCard	16	51–55
Amex	15	34, 37
Diners	16	300–303, 36, 38
Discover	16	6011
EnRoute	15	2014, 2149
JCB	16	3528–3589
Voyager	15	8699

Development

npm ci
npm test               # run the unit tests
npm run test:coverage  # run the unit tests with coverage
npm run check          # typecheck, test with coverage, build and lint the package

Releasing

1. Bump the version with npm version <major|minor|patch> --no-git-tag-version and describe the changes in CHANGELOG.md.
2. Merge the changes into master.
3. Run the Node.js Package workflow on master. It checks and publishes the package and creates the GitHub release with the changelog entry. Publishing a GitHub release whose tag equals the package version publishes the package as well.