Phone Verification

Phone verification in TrustGate is a passive intelligence capability built into the Device Intelligence service. It validates phone numbers and assesses risk based on phone type, carrier, fraud score, and abuse signals -- all without requiring the user to interact with an OTP flow.

Under the hood, phone intelligence is powered by a fraud intelligence provider.

Part of Device Intelligence

Phone verification is not a standalone endpoint. To run a phone check, include the phone and phone_country parameters when calling the Device Intelligence analyze endpoint.

Running a Phone Check

Submit a phone number as part of a device intelligence analysis:

curl -X POST https://api.bytrustgate.com/api/v1/device-intel/analyze \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "ip_address": "203.0.113.1",
    "phone": "+14155551234",
    "phone_country": "US",
    "applicant_id": "550e8400-e29b-41d4-a716-446655440000"
  }'

Parameter	Type	Required	Description
`ip_address`	string	Yes	IP address for device analysis
`phone`	string	No	Phone number to validate (E.164 format recommended)
`phone_country`	string	No	ISO 2-letter country code for number formatting
`applicant_id`	UUID	No	Associate the check with an applicant

Response

The response includes a phone_check object alongside the other device intelligence results:

{
  "phone_check": {
    "phone": "+14155551234",
    "valid": true,
    "fraud_score": 15,
    "line_type": "mobile",
    "carrier": "Verizon",
    "country": "US",
    "risky": false,
    "recent_abuse": false
  }
}

Phone Check Fields

Field	Type	Description
`phone`	string	The phone number that was checked
`valid`	boolean	Whether the phone number is valid and active
`fraud_score`	integer	Risk score from 0 (safe) to 100 (high risk)
`line_type`	string	Phone line type: `mobile`, `landline`, `voip`, `toll_free`, `premium`, etc.
`carrier`	string	Carrier or provider name
`country`	string	ISO country code where the number is registered
`risky`	boolean	Whether the number has been flagged as risky
`recent_abuse`	boolean	Whether the number has been associated with recent abuse

Phone Types

Type	Description	Risk Level
`mobile`	Standard mobile phone	Low
`landline`	Fixed landline	Low
`voip`	Voice over IP	Medium
`toll_free`	1-800 numbers	High
`premium`	Premium rate numbers	High
`virtual`	Virtual numbers	Medium-High

Risk Factors

High Risk

Factor	Risk Contribution	Description
`fraud_history`	+40	Phone linked to fraud
`premium_rate`	+30	Premium rate number
`recently_ported`	+20	Number ported in last 30 days
`known_fraud_carrier`	+35	Carrier associated with fraud

Medium Risk

Factor	Risk Contribution	Description
`voip_number`	+15	VoIP provider number
`virtual_number`	+20	Virtual phone service
`prepaid`	+10	Prepaid SIM card
`country_mismatch`	+15	Phone country differs from applicant

Low Risk

Factor	Risk Contribution	Description
`new_number`	+5	Number recently activated
`unusual_carrier`	+5	Less common carrier

VoIP Detection

TrustGate detects VoIP numbers through its fraud intelligence provider and flags them with a higher fraud score. When a VoIP number is detected, the line_type field returns "voip" and the valid field may be set to false depending on risk thresholds.

Example: VoIP Number Detected

{
  "phone_check": {
    "phone": "+14155559999",
    "valid": false,
    "fraud_score": 45,
    "line_type": "voip",
    "carrier": "Google Voice",
    "country": "US",
    "risky": true,
    "recent_abuse": false
  }
}

When a phone check fails validation, the response includes reason codes to help you understand why:

Reason Code	Description
`voip_detected`	VoIP phone numbers have higher fraud risk
`high_fraud_score`	Phone number associated with suspicious activity (fraud score >= 85)
`risky_number`	Phone number flagged as potentially risky
`invalid_number`	Unable to validate the phone number

Workflow Rules

Flag VoIP Numbers for Review

curl -X POST https://api.bytrustgate.com/api/v1/workflows/rules \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "rule_id": "flag_voip_phones",
    "trigger": "device_analysis_complete",
    "conditions": {
      "all": [
        {"field": "phone_check.line_type", "operator": "eq", "value": "voip"}
      ]
    },
    "actions": [
      {
        "type": "add_flag",
        "flag": "voip_phone"
      },
      {
        "type": "request_info",
        "info_needed": "VoIP number detected - manual review recommended"
      }
    ]
  }'

Flag High Fraud Score Phones

curl -X POST https://api.bytrustgate.com/api/v1/workflows/rules \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "rule_id": "flag_high_risk_phone",
    "trigger": "device_analysis_complete",
    "conditions": {
      "all": [
        {"field": "phone_check.fraud_score", "operator": "gte", "value": 75}
      ]
    },
    "actions": [
      {
        "type": "add_flag",
        "flag": "high_risk_phone"
      },
      {
        "type": "create_case",
        "case_type": "fraud",
        "priority": "high",
        "title": "High fraud score phone number detected"
      }
    ]
  }'

Programmatic Access

Phone verification is also available as a standalone primitive for use in custom pipelines:

from app.primitives.device_intel import PhoneCheckPrimitive

result = await PhoneCheckPrimitive.run(
    phone="+14155551234",
    phone_country="US"
)

Next Steps

Risk Signals - All fraud signals explained
Email Verification - Email risk assessment
Device Intelligence - Device fingerprinting

Running a Phone Check​

Response​

Phone Check Fields​

Phone Types​

Risk Factors​

High Risk​

Medium Risk​

Low Risk​

VoIP Detection​

Example: VoIP Number Detected​

Workflow Rules​

Flag VoIP Numbers for Review​

Flag High Fraud Score Phones​

Programmatic Access​

Next Steps​