API Overview

Unified Checkout Developer Guide
- Recent Revisions to This Document

Introduction to Unified Checkout

Unified Checkout Quick Start
- Step 1: Enable Unified Checkout
- Step 2: Set Up the Server-Side Component
- Step 3: Set Up the Client-Side Component
- Step 4: Configure Unified Checkout
- Step 5: Test Your Unified Checkout Integration

Unified Checkout Flow

Server-Side Set Up

Client-Side Set Up
- Loading the JavaScript Library
- Complete Integration Examples

Configuration
- Configure the Unified Checkout Merchant Experience
  - Enable Unified Checkout
  - Configure Payment Options
  - Customize the Unified Checkout Look and Feel
  - Look and Feel UI Examples
  - Configure Customer Data and Payment Flow
  - Capture Context Fields in the Smartpay Fuse Portal
  - Manage Permissions
    - Managing Permissions as an Administrator
- Process Payments with Unified Checkout
- Webhooks Support

Transient Tokens
- Transient Token Format
- Token Verification
- Dual-Branded Cards
- Authorizations with a Transient Token

Test Your Configuration
- Unified Checkout Test Cards
- Visa and Mastercard Click to Pay Test Cards
- Test Cards for Authentication by Click to Pay
- Test Authentication
- Handle Errors
- Reason Codes

Payment Details API

JavaScript API Reference

Appendix
- JSON Web Tokens
- Supported Countries for Digital Payments
- Supported Locales
- Update to Unified Checkout Version 1
  - Update Reason Codes
  - Version 1 Update Checklist
- Security Recommendations
- PCI Compliance

On This Page

Update Reason Codes

Some reason codes were renamed in v1. This table shows the v0 reason code name and the corresponding name in the v1 client-side SDK:

v0 Reason Code	v1 Reason Code
SHOW_LOAD_CONTAINER_SELECTOR	MOUNT_CONTAINER_SELECTOR
SHOW_LOAD_ERROR	MOUNT_ERROR
SHOW_LOAD_INVALID_CONTAINER	MOUNT_INVALID_CONTAINER
SHOW_LOAD_SIDEBAR_OPTIONS	MOUNT_SIDEBAR_OPTIONS
SHOW_PAYMENT_TIMEOUT	MOUNT_PAYMENT_TIMEOUT
SHOW_PAYMENT_UNAVAILABLE	MOUNT_PAYMENT_UNAVAILABLE
SHOW_TOKEN_TIMEOUT	MOUNT_TOKEN_TIMEOUT
SHOW_TOKEN_XHR_ERROR	MOUNT_TOKEN_XHR_ERROR
UNIFIED_PAYMENTS_ALREADY_SHOWN	CHECKOUT_ALREADY_MOUNTED
UNIFIED_PAYMENTS_PAYMENT_PARAMETERS	CHECKOUT_PAYMENT_PARAMETERS
UNIFIED_PAYMENTS_VALIDATION_PARAMS	CHECKOUT_VALIDATION_PARAMS

IMPORTANT

The server-side API continues to return these v0 reason codes. The v1 reason codes listed here are used only in the client-side SDK. For all v1 client-side error codes, see Handle Errors.

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