Fraud Detection

Fraud Detection is designed to give information which can help to identify phone numbers associated with fraud for application integrations. This API is currently in Beta.

This API will be sunset on November 23, 2025, and will no longer be available after that date.

To detect SIM Swap, please migrate to the Identity Insights API.

Download OpenAPI Specification
Available Operations

Check for Fraud

Make fraud check requests with a phone number by checking SIM swap status.

posthttps://api.nexmo.com/v2/ni

Authentication

KeyDescriptionWhereExample
Authorization

Base64 encoded API key and secret joined by a colon.
Read more

Headers

Basic <base64>

Request Body
Content Type
application/json

type
string
Required
examplephone

Accepted value is “phone” when a phone number is provided.

Must be one of:phone
phone
string
Required
example447009000000

A single phone number that you need insight about in the E.164 format. Don't use a leading + or 00 when entering a phone number, start with the country code, e.g. 447700900000.

insights
array
Required

The insight you require. Must be: sim_swap.

Available Values:
sim_swap

Example Request

{
   "type": "phone",
   "phone": "447009000000",
   "insights": [
      "sim_swap"
   ]
}

Responses
Content Type
application/json

OK

request_id
string
Required
example3f92ed75-e624-4503-abbd-a93d6b442571

Unique UUID for this request for reference.

type
string
Required
examplephone

The type of lookup used in the request. Currently always phone.

phone
object
Required

An object containing the phone number that was used in the fraud check.

phone
string
Required
example16197363066

The phone number used in the fraud check operation(s).

sim_swap
object

The result of the sim_swap insight operation. If successful, it will return swapped: true if the sim was swapped in the last 7 days.

The sim_swap object will only be returned if you specified sim_swap as a value in the insights array when the request was made.

status
string
Required
examplecompleted

The status of the sim_swap call.

Must be one of:completedfailed
swapped
boolean
exampletrue

true if the sim was swapped in the last 7 days, false otherwise. Returned only if the sim swap check succeeds.

reason
string
exampleMobile Network Operator Not Supported

The reason for a sim swap error response. Returned only if the sim swap check fails.

Example Response

{
   "request_id": "3f92ed75-e624-4503-abbd-a93d6b442571",
   "type": "phone",
   "phone": {
      "phone": "16197363066"
   },
   "sim_swap": {
      "status": "completed",
      "swapped": false
   }
}