API Overview

Documentation Release Notes
- September 2026
  - Acceptance Devices | PAX All-in-One Android Solution Integration Guide
  - Acceptance Devices | Tap to Pay on Android Solution Integration Guide
  - Acceptance Devices | Tap to Pay on iPhone Solution Integration Guide
  - Digital Accept Secure Integration Developer Guide
  - Independent Software Vendors
  - OAuth 2.0 Partner Implementation Guide
  - Unified Checkout Developer Guide
  - Unified Click to Pay Developer Guide
- August 2026
  - Acceptance Devices | PAX All-in-One Android Solution Integration Guide
  - Acceptance Devices | Tap to Pay on Android Solution Integration Guide
  - Click to Pay Drop-In UI Developer Guide
  - Credentialed Transactions Developer Guide
  - Digital Accept Secure Integration Developer Guide
  - Invoicing Developer Guide
  - Merchant Boarding User Guide
  - Pay by Link Developer Guide
  - Payer Authentication Developer Guide
  - Simple Order API Field Reference
  - Unified Checkout Developer Guide
- July 2026
  - Acceptance Devices | PAX A77 Terminal User Guide
  - Acceptance Devices | PAX A920 MAX Terminal User Guide
  - Acceptance Devices | PAX A920 PRO Terminal User Guide
  - Acceptance Devices | PAX All-in-One Android Solution Integration Guide
  - Acceptance Devices | PAX IM30 Terminal User Guide
  - Acceptance Devices | Tap to Pay on Android Solution Integration Guide
  - BIN Lookup Service Developer Guide
  - Getting Started with REST Developer Guide
  - P12 Authentication Upgrade for SOAP Toolkit Key Users Migration Guide
  - Unified Checkout Developer Guide
  - Unified Click to Pay Developer Guide
- June 2026
  - Acceptance Devices | PAX Acceptance Devices App
  - Acceptance Devices | PAX All-in-One Android Solution
  - Acceptance Devices | Tap to Pay on Android Acceptance Devices App
  - Acceptance Devices | Tap to Pay on Android Solution
  - Acceptance Devices | Tap to Pay on iPhone Solution
  - Card Present Connect | Mass Transit
  - Getting Started with REST
  - Secure Acceptance to Unified Checkout
  - Simple Order API Field Reference
- May 2026
  - Acceptance Devices | PAX Acceptance Devices App
  - Acceptance Devices | PAX All-in-One Android Solution
  - Acceptance Devices | Tap to Pay on Android Acceptance Devices App
  - Acceptance Devices | Tap to Pay on Android Solution
  - Card Present Connect | Electric Vehicle Charging
  - Card Present Connect | Lodging
  - Click to Pay Drop-In UI
  - P12 Authentication Upgrade for SOAP Toolkit Key Users
  - Paze
  - Recurring Billing
- April 2026
  - Acceptance Devices | PAX All-in-One Android Solution
  - Acceptance Devices | Tap to Pay on Android Solution
  - Getting Started with REST
  - OAuth
  - Payments
  - Simple Order API Field Reference
  - Unified Checkout
  - Unified Click to Pay
- March 2026
  - Acceptance Devices | PAX Acceptance Devices App
  - Acceptance Devices | PAX All-in-One Android Solution
  - Acceptance Devices | Tap to Pay on Android Acceptance Devices App
  - Acceptance Devices | Tap to Pay on Android Solution
  - Acceptance Devices | Tap to Pay on iPhone Solution
  - Healthcare Processing
  - Klarna Integration
  - Payer Authentication
  - Simple Order API Field Reference
  - Unified Checkout
  - Unified Click to Pay
- February 2026
  - Acceptance Devices | PAX A35 Terminal
  - Acceptance Devices | PAX A920 Terminal
  - Acceptance Devices | PAX A920 MAX Terminal
  - Acceptance Devices | PAX Acceptance Devices App
  - Acceptance Devices | PAX All-in-One Android Solution
  - Acceptance Devices | PAX IM30 Terminal
  - Acceptance Devices | Tap to Pay on Android Acceptance Devices App
  - Acceptance Devices | Tap to Pay on Android Solution
  - Acceptance Devices | Tap to Pay on iPhone Solution
  - Card Present Connect | Electric Vehicle Charging
  - Card Present Connect | Mass Transit
  - Credentialed Transactions
  - Getting Started with REST
  - Invoicing
  - Pay by Link
  - REST API Field Reference
  - Unified Click to Pay
- January 2026
  - Acceptance Devices | PAX All-in-One Android Solution
  - Acceptance Devices | Tap to Pay on Android Solution
  - Acceptance Devices | Tap to Pay on iPhone Solution
  - Card Present Connect | Retail
  - Payer Authentication
  - PIN Debit Processing
  - Secure Acceptance to Unified Checkout Migration
  - Simple Order API Field Reference
  - Visa Currency Conversion
- December 2025
  - Acceptance Devices | PAX Acceptance Devices App
  - Acceptance Devices | PAX All-in-One Android Solution
  - Acceptance Devices | Tap to Pay on Android Acceptance Devices App
  - Acceptance Devices | Tap to Pay on Android Solution
  - Card Present Connect | Mass Transit
  - Click to Pay Drop-In UI
  - Digital Accept Secure Integration
  - Getting Started with REST
  - Unified Checkout
- November 2025
  - Acceptance Devices | PAX A35 Terminal
  - Acceptance Devices | PAX A77 Terminal
  - Acceptance Devices | PAX A920 Terminal
  - Acceptance Devices | PAX A920 MAX Terminal
  - Acceptance Devices | PAX A920 PRO Terminal
  - Acceptance Devices | PAX All-in-One Android Solution
  - Acceptance Devices | PAX IM30 Terminal
  - Acceptance Devices | Tap to Pay on Android Solution
  - Digital Accept Secure Integration
  - Getting Started with REST
  - Invoicing
  - OAuth 2.0
  - Unified Checkout
- October 2025
  - Acceptance Devices | PAX Acceptance Devices App
  - Acceptance Devices | PAX All-in-One Android Solution
  - Acceptance Devices | Tap to Pay on Android Acceptance Devices App
  - Acceptance Devices | Tap to Pay on Android Solution
  - Click to Pay Drop-In UI
  - Digital Accept Secure Integration
  - Unified Checkout
  - Webhooks

On This Page

Unified Click to Pay Developer Guide

26.09.01

Added client versions 0.8, 0.9, and 0.10 to the client version history, with detailed change descriptions for each release. See Client Version Changes.

Updated the client version summary to include client versions 0.8, 0.9, and 0.10. See Client Version History.

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