canada-sin

Validate and generate Canadian Social Insurance Numbers (SIN) using the Luhn checksum algorithm. Written in TypeScript, built with Vite, shipped as both ESM and CommonJS.

Generated SINs are structurally valid test data (they pass the same checksum real SINs use) — they are not real, assigned Social Insurance Numbers.

Install

npm install canada-sin

Usage

import { isValidSIN, generateSIN } from "canada-sin";

isValidSIN("046 454 286"); // true
isValidSIN("123-456-789"); // false (bad checksum)
isValidSIN("12345");       // false (wrong length)

generateSIN(); // e.g. "728194625" — a fresh, structurally valid SIN

CommonJS:

const { isValidSIN, generateSIN } = require("canada-sin");

API

isValidSIN(sin: string | number): boolean

Returns true if sin, once non-digit characters (spaces, dashes) are stripped, is exactly 9 digits long and satisfies the Luhn checksum.

generateSIN(): string

Returns a random 9-digit string that satisfies isValidSIN. The first digit is always 1-9 (real SINs never start with 0); the remaining digits are randomized, and the final digit is computed as the correct Luhn check digit.

Development

npm install
npm test        # run unit tests (Vitest)
npm run build   # build dist/ (ESM + CJS + types) with Vite

References

• wealthsimple/social-insurance-number — the reference implementation this package's algorithm and API were based on.
• ShirtlessKirk's Luhn algorithm gist — origin of the lookup-table Luhn checksum technique used here.
• Luhn algorithm — Wikipedia — background on the checksum algorithm itself.

License

MIT