Getting Started

The Payrexx Cash Register integration enables easy integration of our card readers.

As Payrexx continues to expand its support for Point-of-Sale (POS) solutions, the variety of hardware terminals we integrate also grows. We understand that developing for different hardware providers can be a significant challenge. Each new terminal model often comes with its own integration logic, processes, and quirks.

To simplify development and standardize hardware interaction, we've created the Payrexx Cash Register API based on our Merchant API.

Consult the Merchant API for more information.

Our Philosophy: The Standardization Layer

The purpose of the Cash Register API is to provide one single and consistent interface for your software to communicate with any Payrexx-supported hardware terminal.

Instead of your application needing to know how to "speak" to a terminal, and then learn a completely new "language" for another brand, you only need to learn one: the Payrexx Cash Register API.

You write your integration once against our API. We handle the complex work of "translating" your request to the specific terminal you're using.

This philosophy ensures that as we add new hardware providers to our ecosystem, your existing integration will continue to work with minimal to no changes on your end.

Current Support

Currently, the Cash Register API provides full support for NexGo devices. As we integrate more hardware providers, they will be made available through this same standardized API, simplifying your future development work.

---

How It Works: A Quick Tour

The API is logically broken down into three main groups of endpoints, covering the full lifecycle of a terminal's operation.

1. 🤝 PAIRING: The "Handshake"

Before you can send a payment to a terminal, your system needs to know it exists. Pairing is the "handshake" that links a physical terminal (using its serial number) to the API, making it available for requests.

• pair GET: Checks the current status of a terminal (e.g., is it paired and ready?).

• pair POST: Registers a new terminal. You pass in its serial number, and the API links it to your account for further use.

• pair DELETE: Frees a terminal from the API pairing (e.g., when decommissioning a device).

Pairing Flow

Unpair Flow

2. 💳 PAYMENT: The Main Event

This is the core of the API—how you handle transactions. This group manages everything from starting a payment to checking its status or reversing it.

• payment GET: Retrieves the status and details of a specific payment by its ID (e.g., "Was this successful? Declined?").

• payment POST: The primary endpoint for initiating a transaction. This sends a payment request (e.g., "charge 25.50") to a specific paired terminal.

• payment/cancel POST: Used to cancel a payment that is currently in progress on the terminal.

• payment/void POST: Used to cancel a payment that has already been completed (typically a "day-of" cancellation before the batch is settled).

Note on Refunds: The payment/refund POST endpoint is part of the API standard but is not yet enabled for NexGo devices.

Paired Payment Flow

3. ⚙️ ADDITIONAL: Utilities

This group contains helpful endpoints that provide more context about a terminal's capabilities.

• paymentMethods POST: Asks a terminal, "What payment methods do you accept?" (e.g., ). This allows you to determine available payment methods for your register

Next Steps

This overview provides the high-level map of the Cash Register API. For the complete technical breakdown—including all required fields, request/response examples, and error codes—please see our detailed Technical API Reference.

Jump to the Technical Docs: View the full API Reference on developers.payrexx.com