The /start API allows you to choose Signals for ID verification. Specify them in the /start signals parameter.

The following table describes each of the available signals.

Signal	Description
`document_liveness_idrnd`	Document probability checks for on-screen presentation, printed copy, and portrait substitution.
`email_validation`	Customer email address check.
`idcheck`	Barcode analysis on North American driver licenses, including real IDs, and extended IDs.
`ocr_match`	Compare OCR scan to barcode or MRZ data.
`ocr_scan`	OCR scan on passport books, passport cards, and other forms of identification.
`selfie`	Facial matching and liveness.

Signal Selection

To selectively apply signals in the /start endpoint, you use the signals parameter in the request body. If you do not provide these parameters, all data for signals to which your company account is subscribed will be returned.

For example, the following /start private_data request body could be used to validate a passport booklet (ocr_scan) and return OCR match results (ocr_match).

{  
  "private_data": {
    "document_type": "passport",
    "signals": [  
      "ocr_match",  
      "ocr_scan"  
    ],      
  }  
}

To additionally obtain the results of a selfie check, (selfie), the /start private_data request body might look like this.

{  
  "private_data": {
    "document_type": "passport",
    "signals": [  
      "ocr_match",  
      "ocr_scan",
      "selfie"
    ],      
  }  
}