# Validator.js — String Validation and Sanitization for JavaScript

> A library of string validators and sanitizers for JavaScript and Node.js covering emails, URLs, credit cards, and dozens of other formats.

## Install

Save in your project root:

# Validator.js

## Quick Use
```bash
npm install validator
```
```js
import validator from 'validator';
validator.isEmail('test@example.com'); // true
```

## Introduction
Validator.js is a library of string validators and sanitizers for JavaScript. It runs in both Node.js and browser environments, giving you a single dependency for checking emails, URLs, UUIDs, credit card numbers, and many more common formats.

## What Validator.js Does
- Validates over 80 string formats including email, URL, IP, UUID, and ISO dates
- Sanitizes input by trimming, escaping HTML, normalizing emails, and stripping low bytes
- Works in Node.js and the browser with zero external dependencies
- Provides locale-aware validation for phone numbers, postcodes, and tax IDs
- Supports custom validation by composing built-in checks

## Architecture Overview
Validator.js is a pure-function library with no classes or state. Each validator and sanitizer is an independent function that takes a string and returns a boolean or transformed string. The library ships as a single ES module with tree-shakeable named exports, keeping bundle size small when you import only what you need.

## Self-Hosting & Configuration
- Install via npm, yarn, or pnpm for Node.js projects
- Import individual validators to reduce bundle size in frontend builds
- No configuration files are needed as each function is self-contained
- Use the sanitizer functions at your API boundary before storing user input
- Pair with schema libraries like Zod or Yup for object-level validation

## Key Features
- Over 80 built-in validators covering common web input patterns
- Locale-specific checks for phone numbers and postal codes across 50+ countries
- Lightweight with zero dependencies and a small bundle footprint
- Consistent API where every function takes a string and options object
- Active maintenance with regular updates for new validation rules

## Comparison with Similar Tools
- **Zod** — validates typed objects and schemas; Validator.js focuses on raw string checks
- **Yup** — schema-based with async support; Validator.js is synchronous string-only
- **joi** — Hapi ecosystem schema validator; Validator.js is framework-agnostic
- **class-validator** — decorator-based for TypeScript classes; Validator.js uses plain functions
- **Valibot** — modular schema builder; Validator.js is a flat collection of string utilities

## FAQ
**Q: Can I use Validator.js in the browser?**
A: Yes. It ships as an ES module and works in any modern browser or bundler.

**Q: Does it validate objects or only strings?**
A: Only strings. For object validation, pair it with a schema library.

**Q: Is it safe to rely on for security-critical input?**
A: It is widely used for input sanitization, but always combine it with server-side checks and parameterized queries.

**Q: How do I add a custom validator?**
A: Compose existing validators in a wrapper function; the library does not have a plugin API.

## Sources
- https://github.com/validatorjs/validator.js
- https://www.npmjs.com/package/validator

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Source: https://tokrepo.com/en/workflows/asset-040a0766
Author: AI Open Source