IP Matching


You can use Nexmo's Number Insight Advanced API to determine whether a user's IP address is in the same location as their phone. This can help you detect potentially fraudulent use of your services.

Making the request

Pass the user's IP address in the ip parameter when you make the request, as shown in the following curl example.

Replace the NEXMO_API_KEY and NEXMO_API_SECRET placeholder variables with your own API key and secret from the developer dashboard.

curl 'https://api.nexmo.com/ni/advanced/json?api_key=NEXMO_API_KEY&api_secret=NEXMO_API_SECRET&number=INSIGHT_NUMBER&ip=&cname=true'

Understanding the response

When you include the ip parameter in the request, the ip field in the response contains an object with the following properties:

Example response

In the following sample response, the user's IP address originates from South Korea (KR), but the user's phone is located in the United Kingdom (GB). The ip_match_level indicates that there is a possible mismatch.

Note: The ip_warnings property is deprecated and can safely be ignored.

    "status": 0,
    "status_message": "Success",
    "lookup_outcome": 1,
    "lookup_outcome_message": "Partial success - some fields populated",
    "request_id": "0aad8f5f-1ff4-404b-9dc2-6fc47737a668",
    "international_format_number": "447700900001",
    "national_format_number": "07700 900001",
    "country_code": "GB",
    "country_code_iso3": "GBR",
    "country_name": "United Kingdom",
    "country_prefix": "44",
    "request_price": "0.03000000",
    "remaining_balance": "5.00",
    "current_carrier": {
        "network_code": "23410",
        "name": "Telefonica UK Limited",
        "country": "GB",
        "network_type": "mobile"
    "original_carrier": {
        "network_code": "23410",
        "name": "Telefonica UK Limited",
        "country": "GB",
        "network_type": "mobile"
    "valid_number": "valid",
    "reachable": "reachable",
    "ported": "not_ported",
    "roaming": {
        "status": "not_roaming"
    "ip": {
        "address": "",
        "ip_match_level": "mismatch",
        "ip_country": "KR",
        "ip_city": ""
    "ip_warnings": "unknown"