Email Validator API | APIVerve API Tutorial

A simple Node.js/Express API service that validates email addresses. Check if emails are real, deliverable, and catch typos before they become bounces.

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Features

• Validate any email address in real-time
• Check MX records and SMTP connectivity
• Detect free vs. company email addresses
• Catch common typos (e.g., gmial.com → gmail.com)
• Simple REST API with JSON responses
• Includes a web UI for testing
• Production-ready error handling

Quick Start

1. Clone this repository

   git clone https://github.com/apiverve/email-validator-node-tutorial.git
   cd email-validator-node-tutorial

2. Install dependencies

   npm install

3. Add your API key

   Open src/config.js and replace the placeholder with your API key:

   API_KEY: 'your-api-key-here'

4. Start the server

   npm start

5. Test it out

   Open http://localhost:3000 in your browser, or use curl:

   curl -X POST http://localhost:3000/validate \
        -H "Content-Type: application/json" \
        -d '{"email": "[email protected]"}'

Project Structure

email-validator-node-tutorial/
├── src/
│   ├── routes/
│   │   ├── validate.js  # Email validation endpoint
│   │   └── health.js    # Health check endpoint
│   ├── config.js        # API key and settings
│   └── index.js         # Express app setup
├── public/
│   └── index.html       # Web UI for testing
├── package.json         # Dependencies
├── screenshot.jpg       # Preview image
├── LICENSE              # MIT license
├── .gitignore           # Git ignore rules
└── README.md            # This file

API Reference

POST /validate

Validates an email address and returns detailed information.

Request Body:

{
  "email": "[email protected]"
}

Response (Valid Email):

{
  "success": true,
  "email": "[email protected]",
  "isValid": true,
  "details": {
    "domain": "gmail.com",
    "username": "test",
    "isFreeEmail": true,
    "isCompanyEmail": false,
    "mxValid": true,
    "smtpValid": true,
    "hasTypo": false
  }
}

Response (Invalid Email):

{
  "success": true,
  "email": "[email protected]",
  "isValid": false,
  "details": {
    "domain": "notarealdomain.xyz",
    "username": "bad",
    "isFreeEmail": false,
    "isCompanyEmail": false,
    "mxValid": false,
    "smtpValid": false,
    "hasTypo": false
  }
}

GET /health

Health check endpoint for monitoring.

{
  "status": "ok",
  "timestamp": "2024-01-15T10:30:00.000Z"
}

Use Cases

Email validation is essential for:

• User Registration - Prevent fake signups and reduce bounces
• Lead Generation - Verify leads before adding to your CRM
• Email Marketing - Clean your lists to improve deliverability
• Contact Forms - Catch typos before users submit
• E-commerce - Ensure order confirmations reach customers
• B2B Sales - Verify business emails for outreach

Validation Checks

The API performs multiple validation checks:

Check	Description
Format	Valid email syntax (regex)
MX Record	Domain has mail servers configured
SMTP	Mail server accepts connections
Typo Detection	Common domain misspellings
Disposable	Temporary/throwaway email services
Free vs Company	Gmail vs corporate domains

Customization Ideas

• Add rate limiting with express-rate-limit
• Store validation results in a database
• Add batch validation for multiple emails
• Integrate with your signup flow
• Add webhook notifications for invalid emails

Related APIs

Explore more APIs at APIVerve:

• Email Disposable Checker - Detect temporary email addresses
• Phone Validator - Validate phone numbers
• DNS Lookup - Query DNS records

License

MIT - see LICENSE

Links

• Get API Key - Sign up free
• APIVerve Marketplace - Browse 300+ APIs
• Email Validator API - API details