---
title: "App-to-App Integration Guide"
source_url: https://docs.rapyd.net/en/app-to-app-integration-guide.html
lang: en
---

# App-to-App Integration Guide

Rapyd Core manages low-level payment processing on PAX and SUNMI terminals: card reading, PIN management, EMV processing, and secure communication with Rapyd systems. External Android apps integrate with the Core using Android intents and broadcasts — no direct library linking required.

**Supported hardware:** PAX and SUNMI terminals

**Minimum SDK:** 23

Contents

Includes the following sections:

- [Android Project Setup](https://docs.rapyd.net/en/android-project-setup.md "Android Project Setup")
- [Quick Start - SALE Transaction](https://docs.rapyd.net/en/quick-start---sale-transaction.md "Quick Start - SALE Transaction")
- [Core Management API](https://docs.rapyd.net/en/core-management-api.md "Core Management API")
- [Transaction API](https://docs.rapyd.net/en/transaction-api.md "Transaction API")
- [Pre-Auth, Completion & Cancel Pre-Auth](https://docs.rapyd.net/en/pre-auth,-completion---cancel-pre-auth.md "Pre-Auth, Completion & Cancel Pre-Auth")
- [Void Transactions](https://docs.rapyd.net/en/void-transactions.md "Void Transactions")
- [Reports & Query API](https://docs.rapyd.net/en/reports---query-api.md "Reports & Query API")
- [Receipt & Print API](https://docs.rapyd.net/en/receipt---print-api.md "Receipt & Print API")
- [UI Helpers](https://docs.rapyd.net/en/ui-helpers.md "UI Helpers")
- [External Approval Flow](https://docs.rapyd.net/en/external-approval-flow.md "External Approval Flow")
- [Offline / Deferred Mode](https://docs.rapyd.net/en/offline---deferred-mode.md "Offline / Deferred Mode")
- [Transaction Types Reference](https://docs.rapyd.net/en/transaction-types-reference.md "Transaction Types Reference")
- [Input Parameters Reference](https://docs.rapyd.net/en/input-parameters-reference.md "Input Parameters Reference")
- [Broadcast Actions Reference](https://docs.rapyd.net/en/broadcast-actions-reference.md "Broadcast Actions Reference")
- [Transaction Result Fields](https://docs.rapyd.net/en/transaction-result-fields.md "Transaction Result Fields")
- [Transaction Status Messages](https://docs.rapyd.net/en/transaction-status-messages.md "Transaction Status Messages")
- [Configuration Fields](https://docs.rapyd.net/en/configuration-fields.md "Configuration Fields")
- [Merchant Configuration Fields](https://docs.rapyd.net/en/merchant-configuration-fields.md "Merchant Configuration Fields")
- [Printer Status Codes](https://docs.rapyd.net/en/printer-status-codes.md "Printer Status Codes")
- [Download Resources](https://docs.rapyd.net/en/download-resources.md "Download Resources")