SMS Deliverability Optimization Guide 2025:
Beyond Validation to 99.2% Inbox Placement

SMS Deliverability Pre-Check Example:

// SMS Deliverability Pre-Check API
async function checkSMSDeliverability(phoneNumber) {
  try {
    const response = await fetch('https://api.phone-check.app/v1/validate', {
      method: 'POST',
      headers: {
        'Authorization': 'Bearer YOUR_API_KEY',
        'Content-Type': 'application/json'
      },
      body: JSON.stringify({
        phone_number: phoneNumber
      })
    });

    const result = await response.json();

    // Check deliverability factors before sending
    if (!result.is_valid) {
      return { sendable: false, reason: 'Invalid phone number' };
    }

    if (result.line_type === 'landline') {
      return { sendable: false, reason: 'Landline cannot receive SMS' };
    }

    if (result.line_type === 'voip') {
      // VoIP numbers may have lower delivery rates
      return { sendable: true, risk: 'medium', reason: 'VoIP number' };
    }

    // Mobile number - optimal for SMS
    return {
      sendable: true,
      risk: 'low',
      carrier: result.carrier,
      country: result.country
    };
  } catch (error) {
    console.error('Deliverability check failed:', error);
    return { sendable: false, reason: 'Service unavailable' };
  }
}