# Generic Code and Formats
source: https://developer.mastercard.com/eligibility-api/documentation/code-and-formats/generic-code-and-formats/index.md

## HTTP Status Codes {#http-status-codes}

| **HTTP Status Code** |  **Description**   |
|----------------------|--------------------|
| 200                  | OK                 |
| 400                  | BAD REQUEST        |
| 401                  | UNAUTHORIZED       |
| 403                  | FORBIDDEN          |
| 404                  | RESOURCE NOT FOUND |

## Error Codes {#error-codes}

### Error Structure {#error-structure}

Mastercard returns errors in the following structure.

```json
{
  "Errors": {
    "Error": [
      {
        "Source": "<source>",
        "ReasonCode": "<unique code>",
        "Description": "<short description of the error>",
        "Recoverable": true/false,
        "Details": "<Optional detailed description of the issue>"
      }
    ]
  }
}
```

### Service Error Codes {#service-error-codes}

To review errors related to eligibility checks such as benefit validation, token verification, product eligibility, and card number mismatches, click here [Eligibility Error Codes](https://developer.mastercard.com/eligibility-api/documentation/code-and-formats/eligibility-error-codes/index.md)

To explore errors associated with widget operations including card number validation and benefit search failures, click here [Widget Error Codes](https://developer.mastercard.com/eligibility-api/documentation/code-and-formats/widget-error-codes/index.md)

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

In addition to service error codes, error codes can also be returned by Mastercard's 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, as well as resolutions to each, on the following page [Gateway Error Codes](https://developer.mastercard.com/platform/documentation/security-and-authentication/gateway-error-codes/).