is it possible to submit a custom form via API call?

is it possible to submit a custom form via API call?

Dear all

I create a custom form as the attachment.
Because both the "Time off balance available" and "Remaining Time off balance" fields are numeric values from another database. I want to submit the form via API call.

I am using the HTTP post method to send the following JSON with the API token to https://server/api/v3/requests

{"request":{
            "description":"Time off/Over time application",
            "requester": {
                "id": "6906",
                "name": "Requester "          
            },            
            "subject":"Time off/Over time application",
           
            "templateid":3906,            
            "udf_pick_5705":{
                "value":"Time Off"
            },            
            "udf_date_5706": {
                "value": "1541060100000"
            },
            "udf_date_5707": {
                "value": "1541146542726"
            },
            "udf_decimal_5708":{
                "value":"10"
            },            
            "udf_decimal_5709":{
                "value":"9"
            }                    
        }};

where 

udf_date_5706 is "End Time"
udf_date_5707 is "Start Time"
udf_decimal_5708 is "Remaining Time off balance"
udf_decimal_5709 is "Time off balance available"
udf_pick_5705 is "Claim Type"


I got the following message:

message: {
    response_status: {
      status_code: 4000,
      messages: [
        {
          status_code: 4001,
          field: 'udf_decimal_5708',
          type: 'failed',
          message: 'Extra key found in JSON'
        }
      ],
      status: 'failed'
    }
  }

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