Comprehensive Overview of Payment System Architecture and Core Components

Payment is the core domain of a company, and the article outlines the typical structure and interaction of payment systems, dividing them into a transaction core and a payment core, and describing their components and workflows.

1. Payment System Overview

Core System Interaction

Business Map

2. Core System Analysis

Transaction Core

The transaction core links business systems with underlying payment mechanisms, allowing business systems to focus on business logic without dealing with payment details.

Transaction Core

Basic Transaction Type Abstraction

Multi‑Table Aggregation & Order Association

Payment Core

The payment core abstracts multiple payment types into four forms: 充值, 提现, 退款, and 转账. It also integrates various payment tools and orchestrates payment commands.

Payment Core Overview

Payment Behavior Orchestration

The goal is to achieve 插件式开发 and configurable payment rules for flexible development.

Exception Handling

Handles scenarios such as duplicate payments, partial payments, amount mismatches, and other exceptions.

Channel Gateway

Fund Management

3. Service Governance

Unified Platform Context

After defining system boundaries and business modeling, the payment platform is split into dozens of services. A unique business identifier is propagated across the entire platform to prevent information loss.

Data Consistency Governance

Large payment companies often adopt strict distributed transaction solutions, sacrificing development efficiency for data stability. The article discusses alternative strategies when distributed transactions are not used.

CAS Validation

Idempotency & Exception Compensation

Reconciliation

Near‑Real‑Time Reconciliation

Database Sharding

Asynchronization

To improve stability and efficiency, the payment flow is heavily asynchronous.

Message Asynchronization

External Payment Call Asynchronization

External payment often requires obtaining a pre‑payment credential from third‑party services, which can cause long response times and block the payment chain; asynchronous gateway services mitigate this issue.

Asynchronous Parallelism

Fund Accounting Asynchronization

Hot Account Separate Processing

Accounting Transaction Splitting

4. Production Practice

Performance Testing

Build load‑testing models that simulate real scenarios, store test data in shadow databases, and monitor both single‑machine and centralized link performance to assess system stability and capacity.

Stability Governance

Core Link Separation

Service Dependency Degradation