Complete SMTP Email Verification Guide

// Multiple email verification example
const emails = [
  'user1@example.com',
  'user2@gmail.com',
  'invalid@nonexistent.domain'
];

const verifyEmail = async (email) => {
  const params = new URLSearchParams({
    email: email,
    verifyMx: true,
    verifySmtp: true,
    detectName: true
  });

  const response = await fetch('https://api.email-check.app/v1-get-email-details?' + params, {
    headers: {
      'accept': 'application/json',
      'x-api-key': 'YOUR_API_KEY'
    }
  });

  return await response.json();
};

// Process emails in parallel
const results = await Promise.all(
  emails.map(email => verifyEmail(email))
);

console.log('Verification results:', results);
// [
//   {
//     "email": "user1@example.com",
//     "validMx": true,
//     "validSmtp": true,
//     "validFormat": true
//   },
//   ...
// ];

// Filter results based on validation status
const validEmails = results.filter(result => result.validFormat && result.validMx && result.validSmtp);
const invalidEmails = results.filter(result => !result.validFormat || !result.validMx || !result.validSmtp);

console.log(`Valid emails: ${validEmails.length}`);
console.log(`Invalid emails: ${invalidEmails.length}`);

async function verifyEmailWithRetry(email, maxRetries = 3) {
  const params = new URLSearchParams({
    email: email,
    verifyMx: true,
    verifySmtp: true,
    detectName: true
  });

  for (let attempt = 1; attempt <= maxRetries; attempt++) {
    try {
      const response = await fetch('https://api.email-check.app/v1-get-email-details?' + params, {
        headers: {
          'accept': 'application/json',
          'x-api-key': 'YOUR_API_KEY'
        }
      });

      if (!response.ok) {
        if (response.status === 429) {
          // Rate limited - exponential backoff
          const delay = Math.pow(2, attempt) * 1000;
          await new Promise(resolve => setTimeout(resolve, delay));
          continue;
        }

        if (response.status >= 500) {
          // Server error - retry
          if (attempt < maxRetries) continue;
        }

        throw new Error(`HTTP ${response.status}: ${response.statusText}`);
      }

      const result = await response.json();

      // Handle different validation results
      if (result.validFormat && result.validMx && result.validSmtp) {
        return { ...result, status: 'deliverable' };
      } else if (!result.validFormat) {
        return { ...result, status: 'undeliverable' };
      } else if (!result.validMx) {
        return { ...result, status: 'risky' };
      } else if (!result.validSmtp) {
        return { ...result, status: 'unknown' };
      } else {
        return { ...result, status: 'unknown' };
      }

    } catch (error) {
      console.error(`Attempt ${attempt} failed:`, error.message);

      if (attempt === maxRetries) {
        return {
          email,
          valid: false,
          error: error.message,
          status: 'error'
        };
      }

      // Wait before retry
      await new Promise(resolve => setTimeout(resolve, 1000 * attempt));
    }
  }
}