Phone Number Risk Assessment & Fraud Scoring Guide 2025:
Complete Methodology for Enterprise Fraud Prevention

Phone Risk Assessment API Implementation:

// Phone-Check.app Risk Assessment API
async function assessPhoneRisk(phoneNumber, userContext) {
  try {
    const response = await fetch('https://api.phone-check.app/v1/risk-assess', {
      method: 'POST',
      headers: {
        'Authorization': 'Bearer YOUR_API_KEY',
        'Content-Type': 'application/json'
      },
      body: JSON.stringify({
        phone_number: phoneNumber,
        user_ip: userContext.ip,
        user_agent: userContext.userAgent,
        account_age_days: userContext.accountAge,
        transaction_type: 'registration', // or 'login', 'payment'
        include_behavioral: true
      })
    });

    const result = await response.json();

    // Risk assessment response structure
    return {
      riskScore: result.risk_score,        // 0-100
      riskLevel: result.risk_level,        // 'low' | 'medium' | 'high' | 'critical'
      recommendation: result.recommendation, // 'allow' | 'verify' | 'block' | 'review'
      signals: result.risk_signals,        // Array of detected risk factors
      confidence: result.confidence,       // Percentage (0-100)

      // Action handling based on risk level
      action: getRiskAction(result.risk_level)
    };
  } catch (error) {
    console.error('Risk assessment failed:', error);
    // Fail securely - require additional verification
    return { action: 'verify', reason: 'Service unavailable' };
  }
}

function getRiskAction(riskLevel) {
  const actions = {
    'low': 'allow',
    'medium': 'verify',  // Require 2FA or email verification
    'high': 'review',    // Manual review or step-up authentication
    'critical': 'block'  // Deny the action
  };
  return actions[riskLevel] || 'verify';
}