Phone Number Porting Detection

What is Number Porting?

Number portability allows phone users to keep their number when switching carriers. The FCC mandated this in 2003, and since then over 30% of US phone numbers have been ported at least once.

When a number is ported:

• The phone number stays the same
• The serving carrier changes
• The LRN (Local Routing Number) updates to reflect the new carrier
• The original area code prefix no longer indicates the carrier

Why Detect Porting?

Accurate Carrier Identification

Without porting detection, you can only guess the carrier based on the area code prefix. This is wrong 30%+ of the time. Porting detection tells you:

• Original carrier — Who first owned the number
• Current carrier — Who serves the number now
• Port date — When the last port occurred

Call and SMS Routing

Correct routing requires knowing the actual serving carrier:

• Route calls through appropriate carrier interconnects
• Send SMS through correct carrier gateways
• Avoid routing failures and delays

Fraud Detection

Porting activity patterns can indicate fraud:

• Recent port + high-risk action = potential SIM swap
• Multiple ports in short time = suspicious activity
• Port from major carrier to VoIP = may indicate fraud setup

How Porting Detection Works

The NPAC (Number Portability Administration Center) maintains the authoritative database of all ported numbers. When you perform an LRN lookup, we query this database to return:

curl -X POST https://api-service.verirouteintel.io/api/v1/lrn \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"phone_number": "15551234567"}'

# Response
{
  "data": {
    "phone_number": "15551234567",
    "lrn": "5551230000",
    "carrier": "T-Mobile"
  },
  "success": true
}

Porting Patterns to Watch

Implementation Example

# Check porting status before sensitive operations
def check_phone_risk(phone_number):
    result = veriroute_lookup(phone_number, lrn=True)

    if not result['lrn']['ported']:
        return "LOW_RISK"  # Never ported

    days_since_port = calculate_days(result['lrn']['activation_date'])

    if days_since_port < 7:
        return "HIGH_RISK"
    elif days_since_port < 30:
        return "MEDIUM_RISK"
    else:
        return "LOW_RISK"

Best Practices

1. Always check porting status for routing decisions
2. Use activation date alongside ported status for fraud scoring
3. Don't assume based on area code — always verify
4. Combine with other signals for fraud decisions
5. Cache appropriately — porting status doesn't change frequently