# Add a File to a Dispute Case
source: https://developer.mastercard.com/mastercard-processing-dispute/documentation/use-cases/add-file-to-dispute-case/index.md

## Overview {#overview}

This use case describes the process where a cardholder wants to add a file to an open dispute case, which can be used throughout the chargeback process as supporting documentation.

## Sequence diagram {#sequence-diagram}

Diagram add-file-to-dispute-case

### Explanation {#explanation}

1. The cardholder searches for an open dispute case in the mobile application or e-banking service and selects to add a file to a case.
2. The mobile application or e-banking service sends the request to the server to add the file to a case.
3. The server sends a `POST` request to the `/cases/{case_id}/attachments` endpoint by passing the following mandatory fields in the request body:
   * The `actionCode` field with the value representing your DAM operating model.
   * The file object containing the file name and the source file Base64 encoded. Alert: You can only send a jpg, tiff, or pdf file, and the encrypted payload size cannot exceed 1 MB.
4. The API sends a response to the server, confirming that the file is added to the case in the CMS (DAM).
5. The server sends a response to the mobile application or e-banking service confirming that a file is successfully added.
6. The mobile application or e-banking service notifies the cardholder that the case is updated with the attached file. In the next steps, your Dispute team analyzes the request in DAM and can react accordingly.

Refer to [Sandbox testing](https://developer.mastercard.com/mastercard-processing-dispute/documentation/sandbox-testing/index.md) for more information on how to execute the use case in the Sandbox environment.

## Endpoint {#endpoint}


API Reference: `POST /cases/{case_id}/attachments`