Number Lookup and Caller Identity (CNAM)

Introduction

Number Lookup and CNAM are identity services that answer the questions: "Who owns this number?", "What carrier serves it?", and "What name should display on caller ID?" For NOC engineers, these tools are indispensable for debugging routing issues, verifying number ownership, and understanding why calls show incorrect caller names.

Number Lookup — What It Reveals

A number lookup query returns rich metadata about a phone number:

curl -X GET "https://api.telnyx.com/v2/number_lookup/+15551234567" \
  -H "Authorization: Bearer YOUR_API_KEY"

{
  "data": {
    "phone_number": "+15551234567",
    "country_code": "US",
    "national_format": "(555) 123-4567",
    "carrier": {
      "name": "T-Mobile USA",
      "type": "mobile",
      "mobile_country_code": "310",
      "mobile_network_code": "260"
    },
    "portability": {
      "ported": true,
      "original_carrier": "AT&T",
      "ported_date": "2024-06-15"
    },
    "caller_name": {
      "caller_name": "JOHN SMITH",
      "error_code": null
    },
    "line_type": "mobile",
    "valid": true,
    "fraud_score": 12
  }
}

Key Fields for NOC Use

Field	NOC Use Case
carrier.name	Identify which carrier to troubleshoot with
carrier.type	mobile/landline/voip — affects routing decisions

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