Silent Network Authentication

Introduction

Signzy's Silent Network Authentication APIs provides a secure, frictionless mobile verification mechanism using network-based identity. It enables fintechs and digital platforms to verify a user’s mobile number ownership without OTPs or explicit user input, by leveraging carrier header enrichment

Common Use Cases

Onboarding flows for users

Step-up verification before transactions

Risk screening and SIM-change detection

KYC and compliance pre-checks

How Silent Network Authentication Works

Start the Session Your backend calls the createAuthSession API with the user’s mobile number and (optionally) Mobile IP, a redirect and callback URL. In response, Signzy returns a unique mobile verification link (mobileRedirectUrl).

Open the Verification Link You show this link to your user in mobile browser. When the user opens it on their mobile network (not Wi-Fi), the mobile carrier securely confirms the device and number in the background.

Automatic Verification The network sends back a verification signal silently and the user doesn’t have to enter any code or number. Within a few seconds, the verification is complete.

Get the Result

If you provided a callbackUrl, Signzy automatically sends the result (verified or not) to your server.

If not, you can call the getIdentity API using the requestId from step 1 to fetch the verification status anytime.

Redirect or End Session After the process, the user is either:

Redirected to your specified page (for example, back to your onboarding flow), or

Shown a short completion message if no redirect URL was provided.

Supported Carrier Networks for Silent Auth

T-Mobile

Verizon

Sprint

AT&T

Sample cURL

Production

Pre-Production

curl --location 'https://api.signzy.us/api/v3/silent-auth/createAuthSession' \
--header 'Content-Type: application/json' \
--header 'Authorization: XXXXXX' \
--data '{
   "mobileIP":"",
   "mdnHint":"1XXXXX",
   "redirectUrl":"",
   "callbackUrl":"",
   "showPage":"true",
   "timer": "1000",
   "showVerifScreen":"true",
   "options":{
       "mdnVerify":"true"
   }
}
'

curl --location 'https://api-preproduction.signzy.us/api/v3/silent-auth/createAuthSession' \
--header 'Content-Type: application/json' \
--header 'Authorization: XXXXXX' \
--data '{
   "mobileIP":"",
   "mdnHint":"1XXXXX",
   "redirectUrl":"",
   "callbackUrl":"",
    "showPage":"true",
   "timer": "1000",
   "showVerifScreen":"true",
   "options":{
       "mdnVerify":"true"
   }
}
'

Request Body Parameters

Key	Type	Mandatory	Description
mobileIP	string	optional	The IP address of the mobile device initiating the request. Must be a valid IPv4 or IPv6 address. Empty string allowed.
mdnHint	string	required	The mobile number (MDN) used for authentication. Must match pattern for US Numbers - starts with 1 followed by 10 digits (e.g., 1XXXXXXXXXX).
redirectUrl	string	optional	The URL to which the user will be redirected after authentication. Must be a valid URL. Empty string allowed.
callbackUrl	string	optional	The webhook endpoint to receive the authentication result. Must be a valid URL. Empty string allowed.
showPage	string ("true" / "false")	optional	Key to dictate the behaviour of warning page. If true, user will see a warning page with instruction to turn off the Wifi. Default is "false".
timer	string	optional	Duration in milliseconds for which if the warning page if marked true must be shown. Must be in string between "1000"to "60000".
showVerifScreen	string ("true" / "false")	optional	Whether to show the verification result screen after completion. In case false, the user will see a general message. Default is "false".
options	object	required	Object containing additional configuration options.
options.mdnVerify	string ("true")	required	Indicates if MDN verification should be performed. Must be "true".

Sample Response

{
    "result": {
        "dateTime": "2025-10-06T07:32:41.868Z",
        "requestId": "68e3709a20edce80fXXXXXXX",
        "status": "SUCCESS",
        "sessionId": "608E4C3A-1005-4EFF-AF56-XXXXXXX",
        "mobileRedirectUrl": "https://api.signzy.us/api/v3/silent-auth/identifyDevice?sessionId=608E4C3A-1005-4EFF-AF56-XXXXXXX"
    },
    "reason": "Request Successful",
    "code": "S001"
}

Response Body Parameters

Key	Type	Description
result	object	Contains the response details for the created Silent Auth session.
result.dateTime	string	The timestamp when the request was processed, in ISO-8601 UTC format. Example: 2025-10-06T07:32:41.868Z
result.requestId	string	Unique identifier assigned to the API request for tracking. This will be used in the second API call. Example: 68e3709a20edce80f911XXXX
result.status	string	Indicates the status of the Silent Auth session creation.
result.sessionId	string	Unique identifier for the created Silent Auth session. Used for subsequent verification or device identification calls. Example: 608E4C3A-1005-4EFF-AF56-XXXXXX
result.mobileRedirectUrl	string	URL to which the mobile device should be redirected for device identification. Example: https://api.signzy.us/api/v3/silent-auth/identifyDevice?sessionId=608E4C3A-1005-4EFF-AF56-XXXX
reason	string	Descriptive message explaining the overall response status. Example: Request Successful
code	string	Response code representing the outcome of the API request. Example: S001

Sample Error

### Invalid `mobileIP`
{
  "result": {},
  "reason": "mobileIP must be a valid IP address",
  "code": "E001"
}


### Missing `mdnHint`
{
  "result": {},
  "reason": "mdnHint is required",
  "code": "E001"
}


### Bad `mdnHint` format
{
  "result": {},
  "reason": "mdnHint must be a valid US mobile number (1 + 10 digits)",
  "code": "E001"
}

### Invalid `redirectUrl`
{
  "result": {},
  "reason": "redirectUrl must be a valid URI",
  "code": "E001"
}


### Invalid `callbackUrl`
{
  "result": {},
  "reason": "callbackUrl must be a valid URI",
  "code": "E001"
}


### Invalid `showPage`
{
  "result": {},
  "reason": "showPage must be either \"true\" or \"false\"",
  "code": "E001"
}

### Invalid `showVerifScreen`
{
  "result": {},
  "reason": "showVerifScreen must be either \"true\" or \"false\"",
  "code": "E001"
}

### `timer` not numeric
{
  "result": {},
  "reason": "timer must be a valid number in milliseconds",
  "code": "E001"
}


### `timer` < 1000
{
  "result": {},
  "reason": "timer must be at least 1000ms (1 second)",
  "code": "E001"
}

### `timer` > 60000
{
  "result": {},
  "reason": "timer cannot exceed 60000ms (1 minute)",
  "code": "E001"
}

### Missing `options`
{
  "result": {},
  "reason": "options is required",
  "code": "E001"
}


### Missing `options.mdnVerify`
{
  "result": {},
  "reason": "mdnVerify is required",
  "code": "E001"
}


### `options.mdnVerify` not `"true"`
{
  "result": {},
  "reason": "mdnVerify must be \"true\" only",
  "code": "E001"
}

Error Response Parameters

Parameter	Description
result	Empty result object
reason	Reason for error
code	Error code from Signzy

Error Codes

HTTP Status Code	Error Code	Description
400	E001	Bad Request
401	E101	Unauthorized Access
403	E201	Forbidden
404	E301	not found
409	E401	Upstream error
429	E501	Rate Limit Exceeded
500	E601	Internal Server Error
503	E701	Service Unavailable
504	E801	Timeout

Success Codes

HTTP Status Code	Success Code	Description
200	S001	Request Successful.

Get Identity API

The Get Identity API retrieves verified mobile network information after a successful Silent Auth session. This API uses the requestId obtained from the createAuthSession API to fetch verification results.

API Details

Need to pass the following information. Providing requestId is mandatory.

requestId(required)

Sample cURL

Pre-Production

Production

curl --location 'https://api-preproduction.signzy.us/api/v3/silent-auth/getIdentity' \
--header 'Content-Type: application/json' \
--header 'Authorization: <Auth Token>' \
--data '{
    "requestId": "<requestId>"
}'

curl --location 'https://api.signzy.us/api/v3/silent-auth/getIdentity' \
--header 'Content-Type: application/json' \
--header 'Authorization: <Auth Token>' \
--data '{
    "requestId": "<requestId>"
}'

Request Body Parameters

The API expects the following input in the request payload:

{
    "requestId": "<Request ID> (obtained from the first API)",
}

Parameter	Data Type	Required	Description
requestId	string	Yes	Required Unique request ID generated for the input provided in async API

Sample Response

{
  "result": {
    "requestId": "68e372e820edce80f911XXXX",
    "sessionId": "SESSION-TC001-1759736552703-XXXXX",
    "status": "SUCCESS",
    "mdnVerified": "true"
  },
  "reason": "Request Successful",
  "code": "S001"
}

Response Body Parameters

Key	Type	Description
result	object	Contains verification results for the given requestId.
result.requestId	string	The unique identifier of the request, matching the input requestId.
result.sessionId	string	The unique session identifier associated with the Silent Auth verification process.
result.status	string	Indicates the overall result of the verification. Possible values: SUCCESS, ERROR.
result.mdnVerified	string ("true" / "false")	Indicates whether the MDN (Mobile Directory Number) verification was successful.
reason	string	A human-readable description of the API response outcome. Example: "Request Successful"
code	string	API status code indicating success or failure. Example: "S001" for successful responses.

Sample Error

{
    "result": {},
    "reason": "Session not found for requestId",
    "code": "E301"
}

Error Response Parameters

Parameter	Description
result	Empty result object
reason	Reason for error
code	Error code from Signzy

Error Codes

HTTP Status Code	Error Code	Description
400	E001	Bad Request
401	E101	Unauthorized Access
403	E201	Forbidden
404	E301	Not found
409	E401	Upstream error
429	E501	Rate Limit Exceeded
500	E601	Internal Server Error
503	E701	Service Unavailable
504	E801	Timeout

Success Codes

HTTP Status Code	Success Code	Description
200	S001	Request Successful.
200	S003	Data not Found

Getting help

Please feel free to contact us if you have any questions, require clarification, or have ideas for how to make the documents or any of our services better.

You can reach out to us at [email protected]. We strive to provide prompt and reliable assistance, ensuring your queries are addressed effectively.

We value your feedback and are committed to making your experience smooth and enjoyable. Our team is dedicated to assisting you with any needs you may have. Thank you for choosing our services. We look forward to helping you!