> ## Documentation Index
> Fetch the complete documentation index at: https://developer.hellgate.io/llms.txt
> Use this file to discover all available pages before exploring further.

# Overview

> Process and manage payment transactions

The Payments API provides comprehensive endpoints for processing payments, managing transactions, and handling payment modifications across all Commerce V2 operating models.

## Customer Initiated Payments

These endpoints handle payment processing where the customer is actively present and authorizing the transaction.

Supports multiple payment scenarios:

* **One-off payments**: Single transactions for immediate purchase
* **Initial recurring**: First payment in a subscription series with customer consent
* **Initial unscheduled**: First payment for card-on-file scenarios

All customer-initiated payments optionally support 3-D Secure authentication for enhanced security.

## Merchant Initiated Payments

These transactions occur without direct customer interaction at the time of payment.

Key use cases:

* **Recurring subscriptions**: Automated billing for subscription services
* **Unscheduled transactions**: Variable charges based on usage or consumption
* **Retry logic**: Re-attempt failed payments with stored credentials

All merchant-initiated payments must reference a prior customer-initiated transaction for compliance.

## Payment Modifications

Modify existing payment transactions after initial authorization. Essential for flexible payment management across all operating models.

Available modifications:

* **Capture**: Finalize pre-authorized payments (for two-step payment flows)
* **Void**: Cancel authorized but uncaptured transactions
* **Refund**: Return funds to customers for captured payments

Modifications can be applied across multiple processors, maintaining consistency in multi-processor setups.

## Payment Data

Access comprehensive payment transaction data for reporting, reconciliation, and analysis. Critical for all operating models to maintain transaction visibility.

Features:

* **Transaction history**: Full audit trail of payment lifecycle
* **Multi-processor visibility**: Unified view across all connected processors
* **Real-time status**: Current state of payments with processor responses
* **Filtering capabilities**: Search and filter by multiple criteria

## Refund Data

Access detailed refund transaction data for tracking and reconciliation. Essential for customer service and financial reporting across all operating models.

Provides:

* **Refund status tracking**: Monitor refund processing across processors
* **Transaction linking**: Connect refunds to original payments
* **Partial refund support**: Track multiple refunds against single payments
* **Processor responses**: Detailed feedback from payment processors