---
page_source: https://juspay.io/in/docs/upi-plugin-sdk/cordova/miscellaneous/extended-customer-id-optional
page_title: Extended Customer Id (Optional)
---


# Extended Customer Id



* Device binding requires unique customer id, device id and mobile number combination. Extended customer ID is an optional parameter that is to be used when the same customer wants to do binding on multiple devices with different Mobile numbers.
* For a customer on multiple devices, the extended customer ID will serve as the unique identifier between these devices. The customer ID will be the same for all devices, but the extended customer ID will be different, so that each of the device bindings can be uniquely identified.
  
  > **Warning**
  > Extended Customer Id functionality is only available on Client Auth Token verification Method.
* For implementing this functionality below are things to remember:
  
  
  ### Step 1.1. Keys position in payload
  
  
  * **extendedCustomerId** is to be passed in the SDK payload in string format.Example: “extendedCustomerId”: “ABC123”
  * **** **extended_customer_id**  is to be passed in all Euler API’s related to client auth token.
  
  
  
  **Example payload of session token for Extended Customer Id :-** 
  
  
  #### JSON Code Snippet:
  
  ```json
  {"success":false,"message":"No Data found for the given path"}
  ```
  
  
  > **Note**
  > Extended customer ID is to be passed in all process calls where customer ID is used.