# Retrieve Custom Data
source: https://developer.mastercard.com/mastercard-processing-core/documentation/use-cases/data-management/query-cms-get-particular-data/retrieve-custom-data/index.md

## Overview {#overview}

This use case describes how you fetch the custom data stored in the CMS for the specified client, account contract, or card contract.

## Sequence diagram {#sequence-diagram}

Diagram retrieve-custom-data

### Explanation {#explanation}

1. The server sends a `GET` request to the:
   * `/clients/{client_id}/custom-data/{tag_name}` endpoint to retrieve the custom data for the client
   * `/contracts/{contract_id}/custom-data/{tag_name}` endpoint to retrieve the custom data for the contract (account contract or card contract). The server must pass `accountContractId` or `cardContractId`, respectively, in place of `contract_id` in the path.
2. The API returns the custom data `tagContainer`, `tagName`, and `tagValue` fields for the client, account contract, or card contract depending on what endpoint has been used in the request.

Refer to [Sandbox testing](https://developer.mastercard.com/mastercard-processing-core/documentation/sandbox-testing/data-management/query-cms-to-get-particular-data/retrieve-custom-data/index.md) for information on how to execute the use case in the Sandbox environment.

## Endpoints {#endpoints}


API Reference: `GET /clients/{client_id}/custom-data/{tag_name}`


API Reference: `GET /contracts/{contract_id}/custom-data/{tag_name}`

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