# For Suppliers
source: https://developer.mastercard.com/straight-through-processing/documentation/use-cases/case-3/index.md

## Register a supplier {#register-a-supplier}

Issuers must register the Supplier within the STP system to generate a unique ID that signifies the Issuer-Supplier relationship. This is also known as an STP ID.

The execution steps are as follows:

1. The Issuer makes a `POST` call to the Suppliers endpoint using the Supplier ID provided. The following details are sent in the `POST` call:
   * The appropriate Provider found in the _links.self.href section.
   * The customFields section from the `GET Providers` call with the value parameter in the customFields value section.
2. STP generates the newly linked Supplier and returns a unique STP ID in HATEOAS using the _links.self.href format.

Diagram regsupplier2

\*STP has four different Providers, with each serving the following regions:

* TNS serves North America (NAM) and Latin America and the Caribbean (LAC)
* MPGS-EU serves Europe
* MPGS-AP serves Asia Pacific (AP) and Middle East and Africa (MEA)
* MPGS-IN serves India

From the Providers customFields section, select the key and name of the Provider from the region where your Supplier exists.   

Refer to [Testing](https://developer.mastercard.com/straight-through-processing/documentation/testing/case-3/index.md) for more information on how to execute the use case in the Sandbox environment.

API Reference: `POST /suppliers`

## Retrieve details of a supplier {#retrieve-details-of-a-supplier}

Once a Supplier is registered, the STP system returns a unique STP ID. Please use this STP ID to retrieve details of a Supplier.

The execution steps are as follows:

1. The Issuer makes a `GET` call to the Suppliers endpoint using the STP ID.
2. Returns the Supplier details.

Diagram retdetsupplier2

Refer to [Testing](https://developer.mastercard.com/straight-through-processing/documentation/testing/case-3/index.md) for more information on how to execute the use case in the Sandbox environment.

API Reference: `GET /suppliers/{id}`

## Update details of a supplier {#update-details-of-a-supplier}

Once a Supplier is registered, the STP system returns a unique STP ID. Please use this STP ID to update information for an existing Supplier. Partial updates are not supported.

The execution steps are as follows:

1. The Issuer makes a `PUT` call to the Suppliers endpoint using the STP ID and submits new details.
2. Returns the updated Supplier details.

Diagram updetsupplier2

Refer to [Testing](https://developer.mastercard.com/straight-through-processing/documentation/testing/case-3/index.md) for more information on how to execute the use case in the Sandbox environment.

API Reference: `PUT /suppliers/{id}`