Mastering Payment Channel Cost Billing: Models, Rules, and System Architecture

1. Business Scenarios and Billing Models

Common transaction scenarios such as collection, refund, payout, and authentication each generate channel costs, forming collection‑cost billing, payout‑cost billing, and authentication‑cost billing.

1.1 Collection Scenario

Merchants submit payment requests; banks charge a fee per transaction. The fee schedule varies for credit and debit cards, as shown in the diagram.

1.2 Payout Scenario

Payouts are initiated by platforms to transfer funds to designated recipients, e.g., merchant withdrawals. Fees are usually charged per transaction and can be seen in the payout settlement files.

1.3 Authentication Scenario

Authentication services verify personal and bank‑card information. Each authentication call incurs a fixed fee (e.g., ¥0.20). The cost depends on the number of authentication items and the channel used.

Various billing models exist, such as fixed‑amount per transaction, annual aggregation, tiered amounts, or interest‑based calculations.

2. Protocol and Rule Management

Understanding the relationships among bank agreements, interfaces, and billing rule entries is essential for designing a billing system.

2.1 Bank Agreements and Interfaces

These contracts define fee calculation modes, rates, and collection methods for each channel.

2.2 Billing Rule Entries

Each payment interface may have multiple rule entries to match different transaction attributes (e.g., debit vs. credit, intra‑bank vs. inter‑bank).

2.3 Settlement and Settlement Rules

These rules determine how and when the calculated costs are paid to the channel, including the source bank account and timing.

3. Cost Billing Business Process

The workflow starts from business systems that generate records (payment, payout, authentication, settlement). The process includes data extraction, protocol‑rule matching, cost calculation, aggregation, and settlement matching.

4. Billing Center Product Architecture

The architecture consists of data acquisition, rule management (billing and settlement rules, bank agreements), a core calculation engine, a settlement matching engine, and external data output to routing, accounting, and analytics systems.

5. Adding a New Billing Scenario (Example: Authentication Billing)

Steps include analyzing the scenario, understanding transaction data sources, defining data acquisition methods, specifying data structures, reviewing the authentication agreement, configuring protocol and rule entries, and implementing the workflow.

The resulting design can be applied to other billing scenarios beyond cost billing.