> 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/welcome-to-first-code.md).

# Welcome to First Code

The First Tech Tap to Phone SDK, or simply the SDK, is an Android library designed to securely access the operating system and memory structures, enabling the reading of credit and debit card data—whether from physical cards or digital wallets using contactless technology. By handling the technical complexities of the payments ecosystem, the SDK allows developers to focus on creating a smooth, secure, and efficient checkout experience, with fast integration and lower costs.

Currently, the SDK supports **VISA**, **Mastercard**, and **Elo**, and can be used to develop dedicated payment capture apps or integrate directly into business applications that benefit from open payment networks.

This document is here to help developers troubleshoot errors and issues that may arise when using the SDK. It provides detailed explanations and step-by-step solutions for each identified error. While we've covered most cases, some edge scenarios may still emerge. As new issues are reported by customers and become relevant to the product, they will be added to this documentation.

### Who is this page for?

This page is intended for developers and support teams handling customer-reported issues during coding, deployment, or operation of the product.

### Jump right in

<table data-view="cards"><thead><tr><th></th></tr></thead><tbody><tr><td>Specifications &#x26; Capabilities</td></tr><tr><td>Best Practices &#x26; Requirements for Secure Integration</td></tr><tr><td>Prerequisites &#x26; Requirements</td></tr><tr><td>End-to-End Flow</td></tr><tr><td>Distinguishing Environments: Staging vs. Production</td></tr><tr><td>For Developers: Setting Up the Environment to Get Started</td></tr><tr><td>SDK Calls &#x26; Integration Guide</td></tr><tr><td>Capturing Errors in the Application</td></tr><tr><td>Instructions for Deploying the App to Production</td></tr><tr><td>Glossary of Payment Industry Terms</td></tr><tr><td>Resolving Issues in Testing and Production</td></tr><tr><td>Device Handling Best Practices</td></tr></tbody></table>


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