Best ConvertKit Email Validation API & Subscriber Verification Integration 2025

// Example ConvertKit validation workflow
const validateAndTagSubscriber = async (webhookData) => {
  const { subscriber } = webhookData;
  
  // Validate email with 1lookup
  const validation = await fetch('https://app.1lookup.io/api/v1/email', {
    method: 'POST',
    headers: {
      'Authorization': 'Bearer YOUR_API_KEY',
      'Content-Type': 'application/json'
    },
    body: JSON.stringify({ 
      email: subscriber.email_address 
    })
  });
  
  const result = await validation.json();
  
  // Apply creator-specific tags based on validation
  const tags = ['validated'];
  
  if (result.is_valid && result.risk_level === 'low') {
    tags.push('high-quality-subscriber', 'premium-content-eligible');
  } else if (result.is_valid && result.risk_level === 'medium') {
    tags.push('standard-subscriber', 'nurture-sequence');
  } else if (result.deliverability_score > 70) {
    tags.push('potential-subscriber', 'engagement-test');
  } else {
    tags.push('low-quality', 'review-needed');
  }
  
  // Update ConvertKit subscriber
  await updateConvertKitSubscriber(subscriber.id, {
    tags: tags,
    custom_fields: {
      email_quality_score: result.deliverability_score,
      validation_date: new Date().toISOString()
    }
  });
  
  return { success: true, tags, quality_score: result.deliverability_score };
};