Let's see this case requesting information about the status of the api:

    curl --request GET \
         --url https://unicomusaonline.com/api/v1/status \
         --header 'x-iotopup-user: USER' \
         --header 'x-iotopup-password: PASSWORD' \
         --header 'x-iotopup-key: KEY' 

We have obtained the next answer:

        "response_code": 200,
        "error_message": "",
        "response": {
        "alive": true,
        "success": true,
        "version": "1.0"

Field Description
response_code Integer. Response Code.
error_message String. Error Message. You can read this field if the response_code is different to 200(OK).
response Object. Records.
Code Description
0 General Error. See more details in response field.
200 OK
400 Bad Request
401 Unauthorized
403 Forbidden
404 Not Found
500 Internal Server Error
501 Not Implemented
503 Service Unavaliable
777 Customer Reference Duplicated
Code Description
101 Invalid Phone Number
111 Payment amount outside acceptable range
106 Operator unavailable temporarily. Try again in 30 seconds.
110 Transaction rejected by operator
104 Duplicate Recharge. Try again after 5 minutes.
112 Invalid product
113 Invalid amount
116 An Unknown error occurred while calling the Carrier system. Please try again
117 The phone number of the recipient is not a valid prepaid number
105 The transaction was rejected by the destination operator
Code Description
201 Invalid Credentials
202 Invalid Ani
204 Ani Exist
205 Invalid Server User ID
206 Invalid PIN
207 Invalid PIN length. It should be at least 4 digits
208 The PIN is being used by another customer
209 Invalid dial code
210 Dial Code: Webservice Error
211 The DIAL CODE is being used
212 Invalid Parameters
213 Login not found
214 Customer Not Found
215 Webservice Error
216 Amount exceeds customers balance cannot not process current action
217 Login Exists
218 Invalid Destination Country
219 You cannot cancel the transaction. See the refund policy.