> For the complete documentation index, see [llms.txt](https://ftcoders.first-tech.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://ftcoders.first-tech.com/first-tech-ttp-sdk/user-experience/description-and-purpose-of-the-document.md).

# Description and Purpose of the Document

This document aims to establish **minimum standards for the user experience (UX)** in sales applications that implement the **Tap to Pay (TTP)** payment method. It provides guidance on the design, implementation, and validation of interfaces, flows, and behaviors within applications used by sellers (receiving users) and customers (paying users), with a focus on **efficiency, clarity, accessibility, and regulatory compliance**.

The proposed standardization seeks to:

* Promote a **consistent and intuitive experience** across different points of sale (POS) that use TTP;
* Reduce **operational errors and incomplete transactions** caused by interface issues or interaction ambiguities;
* Improve **user trust** by reinforcing perceptions of security, speed, and convenience;
* Comply with **regulatory requirements** associated with proximity payment methods (e.g., PCI MPoC);
* Facilitate **interoperability between systems** and alignment across product, engineering, support, and compliance teams.

This document is intended for **design, product, engineering, QA, and compliance teams**, and must be used as a **mandatory reference** for the development and validation of any application integrating the TTP payment flow—whether on **mobile devices, Android POS terminals, or web-based sales applications**.

The visual examples and illustrative flows contained in this document are **for guidance purposes only** and do not impose specific visual standards, as long as the described guidelines are faithfully followed regarding user experience, clarity, and expected behavior.


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