Production Ready. Full type coverage.
Designed for production use, with comprehensive type definitions across the entire API surface.
Handle 🇨🇱 RUT values with ease using TypeScript.
Rut.ts provides a comprehensive and battle tested set of functions for working with Chilean RUT values.
Complete. Secure. Reliable.
Small core. Heavily tested.
Production-grade reliability, with 394 test cases covering the 9 core functions.
Lightning fast. Run everywhere.
Lightweight and fast by design. Optimized for frontend workloads and compatible with Bun, Node, Edge, and the browser.
Runs everywhere your TypeScript or JavaScript runs
Zero dependencies and pure TypeScript. Rut.ts behaves identically on Node, Deno, and Bun, at the Edge and on Vercel Functions, and inside any frontend framework — React, Next.js, Astro, or vanilla in the browser.
Get started in seconds
1
Install the library
Add the package with your manager of choice: npm install rut.ts — also works with bun, pnpm, and yarn.
2
Import the function(s)
Pull in only what you need: import { validate, format } from 'rut.ts'. Fully typed and tree-shakeable.
3
Use the function(s)
Call validate('12.345.678-5') to check a RUT, or format('123456785') to clean it up. Strict and safe (non-throwing) modes included.
4
Ship anywhere. Enjoy!
Zero dependencies, zero config. The same code runs on Node, Deno, Bun, the Edge, and the browser.
Built lean,
battle tested;
ready for your use cases
From verifier-digit math to live input formatting — each function does one job well, so you compose only what you need.
FAQs
The RUT (Rol Único Tributario) is Chile's unique identification number, used for tax purposes, legal identification, government services, and banking. It's written as XX.XXX.XXX-Y — a 7–8 digit body followed by a single verifier digit (0–9 or K). For example: 12.345.678-5.
That final character is a check digit derived from the body using the Modulo 11 algorithm, which is what lets a RUT be validated for authenticity without contacting any registry. Computing and verifying it correctly is exactly what rut.ts handles for you.