# 🚀 Robust Email Validator

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> **The most comprehensive email validation library for JavaScript & TypeScript** 📧✨

A lightweight, fast, and developer-friendly email validation library that provides multiple layers of validation including **RFC 5322 compliance**, **DNS/MX record verification**, and **real-time deliverability checking** through popular APIs.

## 🌟 Why Choose Robust Email Validator?

- ✅ **RFC 5322 Compliant** - Industry-standard email format validation
- 🌐 **DNS & MX Verification** - Check if domains can actually receive emails
- 📧 **Deliverability Testing** - Integration with ZeroBounce, Mailgun, and Hunter APIs
- 🚀 **Lightning Fast** - Optimized performance with minimal dependencies
- 🔧 **Highly Configurable** - Choose exactly which validation layers you need
- 📱 **Universal Support** - Works in Node.js, browsers, React, Vue, Angular
- 💪 **TypeScript First** - Full type safety with excellent IntelliSense
- 📊 **Batch Processing** - Validate thousands of emails efficiently
- 🛡️ **Production Ready** - Used by companies worldwide

## 🚀 Quick Start

### Installation

\`\`\`bash
npm install robust-email-validator
\`\`\`

### Basic Usage

\`\`\`javascript
import { EmailValidator } from 'robust-email-validator';

// Quick format validation
const isValid = EmailValidator.validateFormat('user@example.com');
console.log(isValid); // true

// Comprehensive validation
const validator = new EmailValidator({
  checkFormat: true,
  checkDNS: true,
  checkDeliverability: true,
  apiProvider: 'zerobounce',
  apiKey: 'your-api-key'
});

const result = await validator.validate('user@example.com');
console.log(result.isValid); // true/false
console.log(result.details); // Detailed validation results
\`\`\`

## 📋 Table of Contents

- [Features](#-features)
- [Installation](#-installation)
- [Quick Examples](#-quick-examples)
- [API Reference](#-api-reference)
- [Configuration](#-configuration)
- [Browser Support](#-browser-support)
- [Framework Integration](#-framework-integration)
- [Performance](#-performance)
- [Contributing](#-contributing)
- [License](#-license)

## ✨ Features

### 🎯 Multiple Validation Layers

| Feature | Description | Node.js | Browser |
|---------|-------------|---------|---------|
| **Format Validation** | RFC 5322 compliant regex validation | ✅ | ✅ |
| **DNS Verification** | Check if domain exists | ✅ | ❌ |
| **MX Record Check** | Verify mail server configuration | ✅ | ❌ |
| **Deliverability** | Real-time API validation | ✅ | ✅* |

*\*Subject to CORS policies*

### 🔌 API Integrations

- **ZeroBounce** - Industry-leading email validation
- **Mailgun** - Reliable email verification service  
- **Hunter** - Professional email finder and verifier

### 🛠️ Developer Experience

- **Zero Configuration** - Works out of the box
- **Flexible Options** - Enable only what you need
- **Detailed Results** - Comprehensive validation reports
- **Error Handling** - Graceful failure with detailed error messages
- **TypeScript Support** - Full type definitions included

## 📦 Installation

\`\`\`bash
# npm
npm install robust-email-validator

# yarn
yarn add robust-email-validator

# pnpm
pnpm add robust-email-validator
\`\`\`

## 🔥 Quick Examples

### Format Validation Only

\`\`\`javascript
import { EmailValidator } from 'robust-email-validator';

// Synchronous format checking
const emails = [
  'valid@example.com',      // ✅ Valid
  'invalid-email',          // ❌ Invalid
  'user+tag@domain.co.uk'   // ✅ Valid
];

emails.forEach(email => {
  const isValid = EmailValidator.validateFormat(email);
  console.log(\`\${email}: \${isValid ? '✅' : '❌'}\`);
});
\`\`\`

### Comprehensive Validation

\`\`\`javascript
const validator = new EmailValidator({
  checkFormat: true,
  checkDNS: true,
  checkMX: true,
  checkDeliverability: true,
  apiProvider: 'zerobounce',
  apiKey: process.env.ZEROBOUNCE_API_KEY,
  timeout: 10000
});

const result = await validator.validate('user@example.com');

console.log('Email:', result.email);
console.log('Valid:', result.isValid);
console.log('Errors:', result.errors);
console.log('Warnings:', result.warnings);

// Detailed breakdown
if (result.details.format) {
  console.log('Format valid:', result.details.format.isValid);
}
if (result.details.dns) {
  console.log('Domain exists:', result.details.dns.isValid);
  console.log('MX records:', result.details.dns.mxRecords);
}
if (result.details.deliverability) {
  console.log('Deliverable:', result.details.deliverability.isDeliverable);
  console.log('Confidence:', result.details.deliverability.confidence);
}
\`\`\`

### Batch Validation

\`\`\`javascript
const emails = [
  'user1@example.com',
  'user2@invalid-domain.xyz',
  'invalid-format-email'
];

const results = await validator.validateBatch(emails);

console.log('Summary:', results.summary);
// { total: 3, valid: 1, invalid: 2, processed: 3, failed: 0 }

results.results.forEach(result => {
  console.log(\`\${result.email}: \${result.isValid ? '✅' : '❌'}\`);
});
\`\`\`

### Browser Usage

\`\`\`javascript
// Browser-safe configuration
const validator = new EmailValidator({
  checkFormat: true,
  checkDeliverability: true,
  apiProvider: 'mailgun',
  apiKey: 'your-mailgun-key'
});

// Use in form validation
document.getElementById('email-form').addEventListener('submit', async (e) => {
  e.preventDefault();
  const email = document.getElementById('email').value;
  
  const result = await validator.validate(email);
  if (result.isValid) {
    // Proceed with form submission
    console.log('Email is valid!');
  } else {
    // Show validation errors
    console.log('Errors:', result.errors);
  }
});
\`\`\`

## 🔧 Configuration Options

\`\`\`typescript
interface EmailValidationOptions {
  checkFormat?: boolean;        // Default: true
  checkDNS?: boolean;          // Default: false
  checkMX?: boolean;           // Default: false
  checkDeliverability?: boolean; // Default: false
  apiProvider?: 'zerobounce' | 'mailgun' | 'hunter';
  apiKey?: string;
  timeout?: number;            // Default: 5000ms
}
\`\`\`

### Recommended Configurations

\`\`\`javascript
// Real-time form validation (fast)
const formValidator = new EmailValidator({
  checkFormat: true
});

// Registration validation (balanced)
const registrationValidator = new EmailValidator({
  checkFormat: true,
  checkDNS: true
});

// Enterprise validation (comprehensive)
const enterpriseValidator = new EmailValidator({
  checkFormat: true,
  checkDNS: true,
  checkMX: true,
  checkDeliverability: true,
  apiProvider: 'zerobounce',
  apiKey: process.env.ZEROBOUNCE_API_KEY
});
\`\`\`

## 🌐 Framework Integration

### React

\`\`\`jsx
import { useState } from 'react';
import { EmailValidator } from 'robust-email-validator';

function EmailInput() {
  const [email, setEmail] = useState('');
  const [isValid, setIsValid] = useState(null);

  const validateEmail = async (value) => {
    const result = await EmailValidator.isValid(value);
    setIsValid(result);
  };

  return (
    <input
      type="email"
      value={email}
      onChange={(e) => {
        setEmail(e.target.value);
        validateEmail(e.target.value);
      }}
      style={{ borderColor: isValid === false ? 'red' : 'green' }}
    />
  );
}
\`\`\`

### Vue

\`\`\`vue
<template>
  <input
    v-model="email"
    @input="validateEmail"
    :class="{ invalid: !isValid }"
    type="email"
  />
</template>

<script>
import { EmailValidator } from 'robust-email-validator';

export default {
  data() {
    return {
      email: '',
      isValid: null
    };
  },
  methods: {
    async validateEmail() {
      this.isValid = await EmailValidator.isValid(this.email);
    }
  }
};
</script>
\`\`\`

### Angular

\`\`\`typescript
import { Component } from '@angular/core';
import { EmailValidator } from 'robust-email-validator';

@Component({
  selector: 'app-email-input',
  template: \`
    <input
      [(ngModel)]="email"
      (input)="validateEmail()"
      [class.invalid]="!isValid"
      type="email"
    />
  \`
})
export class EmailInputComponent {
  email = '';
  isValid: boolean | null = null;

  async validateEmail() {
    this.isValid = await EmailValidator.isValid(this.email);
  }
}
\`\`\`

## 📊 Performance Benchmarks

| Operation | Time | Memory |
|-----------|------|--------|
| Format validation | ~0.1ms | ~1KB |
| DNS validation | ~100ms | ~2KB |
| API validation | ~500ms | ~3KB |
| Batch (100 emails) | ~2s | ~10KB |

## 🤝 Contributing

We welcome contributions! Please see our [Contributing Guide](CONTRIBUTING.md) for details.

### Development Setup

\`\`\`bash
git clone https://github.com/otitoju/robust-email-validator.git
cd robust-email-validator
npm install
npm test
\`\`\`

## 📄 License

MIT © [Your Name](https://github.com/otitoju)

## 🙏 Acknowledgments

- RFC 5322 specification
- Email validation community
- All contributors and users

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**[⭐ Star us on GitHub](https://github.com/otitoju/robust-email-validator)** • **[📖 Documentation](https://github.com/otitoju/robust-email-validator#readme)** • **[🐛 Report Bug](https://github.com/otitoju/robust-email-validator/issues)** • **[💡 Request Feature](https://github.com/otitoju/robust-email-validator/issues)**

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