# Overview

Alipay+ Code-scanning payment standards are developed by Alipay+ to facilitate interoperability among the following participants:

-   **User**: an individual who has entered into a User Agreement with, and obtains a Payment Product from, an MPP.
-   **MPP** (Mobile Payment Provider): an entity in its capacity as a payment service provider where it issues a Mobile Payment Product to a User, enters into a User Agreement with a User, or processes a Transaction for a User.
-   **Merchant**: a natural or legal person that enters into a Transaction with a User, which is acquired by an ACQP.
-   **ACQP** (Acquiring Service Provider): an entity in its capacity as an acquirer or payment processor, including where it enters into a Merchant Agreement with a Merchant, and processes Transactions for its Merchants.

Alipay+ Code-scanning payment standards are applicable to two types of transaction scenarios:

-   **UPM** (User Presented Mode): the User uses a mobile application (for example, a digital wallet provided by an MPP) to present a code image to the Merchant, and the Merchant scans the code image to initiate a Payment.

The code used in this scenario is called **Payment Code.**

-   **MPM** (Merchant Presented Mode): the Merchant presents a code image to the User, and the User uses a mobile application (for example, a digital wallet provided by an MPP) to scan the code image and initiate a Payment.

The code used in this scenario is called **Collection Code.**

Alipay+ Code-scanning payment standards are composed of four parts:

-   [Code format specifications](../code_scanning_payment_standards_mpp/code_format)
-   [Transaction processing guidelines](../code_scanning_payment_standards_mpp/transaction_processing)
-   [User experience design guidelines](../code_scanning_payment_standards_mpp/user_experience_design)
-   [Security guidelines](../code_scanning_payment_standards_mpp/security)