# Code and Formats
source: https://developer.mastercard.com/currency-conversion-calculator/documentation/code-and-formats/index.md

## HTTP Response and Reason Codes {#http-response-and-reason-codes}

API uses standard HTTP responses.

| Error Code |                                                                                                         Description                                                                                                          |
|------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| 400        | Request with an invalid client ID. If your client ID has not been moved to production. Go to [My Projects](https://developer.mastercard.com/dashboard) and click Request Production Access to request for Production access. |
| 400        | User does not have access to retrieve conversion rates for the requested date                                                                                                                                                |
| 400        | Incorrect request parameter/s. For more information on permitted information, see [Parameters](https://developer.mastercard.com/currency-conversion-calculator/documentation/parameters/index.md)                            |
| 401        | User requests to retrieve conversion rate for a future date. The API only retrieves conversion rates for the current date                                                                                                    |
| 124        | Conversion rate value is less than 0.000001                                                                                                                                                                                  |
| 114        | Conversion rate is not available for this currency pair                                                                                                                                                                      |

### Service Error Response Structure {#service-error-response-structure}

* JSON

```JSON
{
  "name": "settlement-conversion-rate",
  "description": "An error occurred during the request",
  "date": "2020-09-25 21:09:50",
  "type": "error",
  "data": {
    "errorCode": "114",
    "errorMessage": "Not Found , Conversion rate is not available for this currency pair."
  }
}
```

## Gateway Error Codes {#gateway-error-codes}

The error codes can also be returned by the gateway, which is used to verify your request's signature and route it to the correct location.

You can find a list of the errors returned by our gateway and the resolutions to each on [Gateway Error Codes](https://developer.mastercard.com/platform/documentation/security-and-authentication/gateway-error-codes/ "Gateway error").

### Gateway Error Response Structure {#gateway-error-response-structure}

* JSON

```JSON
{
  "Errors": {
    "Error": [
      {
        "Source": "Gateway",
        "ReasonCode": "INVALID_CLIENT_ID",
        "Description": "Project 1ABCeP7Xz1MLytj4BBuaL7YRDCGUR4SjJkG99lFn1674ae08 doesn't have access to the requested service",
        "Recoverable": false,
        "Details": null
      }
    ]
  }
}
```

## ISO Currency Codes {#iso-currency-codes}

Currencies are identified using the 3-character [ISO 4217 alpha-3 currency codes](https://www.iso.org/iso-4217-currency-codes.html) defined by ISO. For example, US dollar is `USD`. This applies to:

* Transaction Currency *\[transCurr\]*
* Cardholder Billing Currency *\[crdhldBillCurr\]*

## Date and Time Formats {#date-and-time-formats}

Date values have 10 characters, specified in the format YYYY-MM-DD. For example, 19 June 2020 is `2020-06-19`. This applies to:

* Transaction Date \[*fxDate\]*