email-guard

Email validation with syntax check, MX lookup and typo suggestions. Zero external dependencies.

Features

• ✅ Syntax validation – checks for valid email format
• 🔍 MX record lookup – verifies the domain can receive emails
• 💡 Typo suggestions – detects common misspellings (gmial.com → gmail.com)
• 🌍 Extended domain list – includes CZ, SK, DE and other European domains
• 0️⃣ Zero dependencies – uses Node.js built-in dns module
• 🔷 TypeScript first – full type definitions included

Install

npm install email-guard

Usage

import { validate } from 'email-guard'

const result = await validate('[email protected]')

// {
//   valid: false,
//   reason: 'mx',
//   suggestion: '[email protected]',
//   validators: {
//     regex: { valid: true },
//     typo:  { valid: true, suggestion: '[email protected]' },
//     mx:    { valid: false, reason: 'MX record not found.' }
//   }
// }

Options

const result = await validate('[email protected]', {
  validateRegex: true,   // default: true
  validateTypo: true,    // default: true
  validateMx: true,      // default: true
  dnsServers: ['8.8.8.8', '1.1.1.1'],  // default
})

Result

import { SyntaxError, TypoError, MxError } from 'email-guard'

interface EmailGuardResult {
    valid: boolean
    reason?: 'regex' | 'typo' | 'mx'          // which validator failed
    suggestion?: string                       // suggested correction
    validators: {
        regex: { valid: boolean; reason?: SyntaxError }
        typo:  { valid: boolean; reason?: TypoError; suggestion?: string }
        mx:    { valid: boolean; reason?: MxError }
    }
}

Error codes

enum SyntaxError {
  Empty        = 'EMAIL_EMPTY',
  MissingAt    = 'EMAIL_MISSING_AT',
  MultipleAt   = 'EMAIL_MULTIPLE_AT',
  MissingLocal = 'EMAIL_MISSING_LOCAL',
  MissingDomain= 'EMAIL_MISSING_DOMAIN',
  MissingTld   = 'EMAIL_MISSING_TLD',
  InvalidChars = 'EMAIL_INVALID_CHARS',
}

enum TypoError {
  TypoDetected = 'TYPO_DETECTED',
}

enum MxError {
  NotFound = 'MX_NOT_FOUND',
}

Examples

// Valid email
await validate('[email protected]')
// { valid: true, validators: { regex: { valid: true }, typo: { valid: true }, mx: { valid: true } } }

// Typo in domain
await validate('[email protected]')
// { valid: false, reason: 'mx', suggestion: '[email protected]', ... }

// TLD typo
await validate('[email protected]')
// { valid: false, reason: 'mx', suggestion: '[email protected]', ... }

// Invalid syntax
await validate('notanemail')
// { valid: false, reason: 'regex', validators: { regex: { valid: false, reason: 'EMAIL_MISSING_AT' } } }

// Skip MX check
await validate('[email protected]', { validateMx: false })
// { valid: true, ... }

// Switch on error codes
import { validate, SyntaxError } from 'email-guard'

const result = await validate(email)
if (result.reason === 'regex') {
    switch (result.validators.regex.reason) {
        case SyntaxError.Empty:      return 'Please enter an email.'
        case SyntaxError.MissingAt:  return 'Email must contain @.'
        case SyntaxError.MissingTld: return 'Domain is missing.'
    }
}

Supported domains for typo detection

Global: gmail.com, yahoo.com, hotmail.com, outlook.com, icloud.com, protonmail.com, proton.me and more.

European: seznam.cz, email.cz, centrum.cz (CZ), zoznam.sk, azet.sk, atlas.sk (SK), web.de, gmx.de (DE/AT).

Want to add more domains? Open a PR.

Node.js requirement

Node.js >= 18.0.0

License

MIT