Build an Adyen Tap to Pay on Android (SoftPOS) integration using the Android Mobile SDK

Steps

1. Confirm device meets requirements: Android 12 or later, Google-certified, integrated NFC, hardware key attestation support, and security patch from March 5, 2022 or later.
2. Add the Adyen Android Mobile SDK to your POS app; obtain an SDK authentication token from Adyen's Customer Area and implement the `AuthenticationProvider` interface to supply the token.
3. Establish a communication session by making a server-to-server API request to Adyen's configuration endpoint using your Adyen API credential.
4. Implement the Tap to Pay payment flow through the Terminal API: send a `PaymentRequest` to the SDK, present the contactless tap prompt to the customer, and await the payment result.
5. Handle the payment result synchronously from the SDK callback; check the `result` field and surface errors from `AdyenReaderError` to your UI.
6. Keep the SDK version current: each SDK version expires six months after release; monitor Adyen release notes and update before the expiry to avoid payment failures.