Overview

The Payment Gateway Service acts as an adapter layer between our internal systems and external payment providers. It abstracts away provider-specific details and provides a unified interface for payment operations.

Key Responsibilities

Gateway Integration

• Connect to multiple payment providers (Stripe, PayPal, Adyen)
• Handle provider-specific API requirements
• Manage API credentials and security
• Route payments to appropriate gateway based on payment method

Authorization & Capture

• Authorize payments (reserve funds)
• Capture authorized payments (charge funds)
• Void authorizations (release holds)
• Handle two-phase commit patterns

Error Handling

• Retry transient failures
• Handle gateway timeouts
• Map provider error codes to internal errors
• Circuit breaker for failing gateways

Supported Payment Gateways

1. Stripe (Primary)

   • Credit/Debit cards
   • ACH payments
   • Digital wallets

2. PayPal (Secondary)

   • PayPal accounts
   • Credit cards via PayPal

3. Adyen (Enterprise clients)

   • International payments
   • Alternative payment methods

Technical Details

Technology Stack:

• Runtime: Java 17
• Framework: Spring Boot
• Circuit Breaker: Resilience4j
• Database: PostgreSQL (gateway transaction mapping)

Performance:

• Gateway Response Time: < 2s (p99)
• Retry Strategy: Exponential backoff, max 3 attempts
• Timeout: 30s per gateway call

Security & Compliance

• PCI DSS Level 1 compliant
• No card data stored (tokenization only)
• TLS 1.3 for all gateway communication
• Secrets stored in HashiCorp Vault