Designing Third‑Party Payment Account Systems: A Deep Dive into Accounting Structures

1. What is third‑party payment?

Third‑party payment refers to independent institutions that have signed agreements with banks and provide transaction support platforms, such as Alipay, Tenpay, and WeChat Pay. In a transaction, the buyer pays using the third‑party platform, which notifies the seller of receipt, and later transfers funds to the seller’s account.

Key questions include the relationship with banks, how funds enter the platform, and how they are settled to merchants.

2. What is an account?

From an accounting perspective, an account is a structured record used to classify and reflect changes in accounting elements. Accounts are divided into general ledger and subsidiary accounts, and by economic content into asset, liability, equity, cost‑expense, and profit‑loss accounts.

Accounts have a left (debit) side for increases and a right (credit) side for decreases, recording details such as name, date, voucher number, summary, amounts, and balance.

Account = transaction flow + balance. Operations on transaction flow and balance must be atomic.

3. Basic account structure

Accounts are often simplified to a “T‑account” format containing name, debit, credit, amount, and balance.

Internal reconciliation ensures consistency between balance and flow within a accounting period; external reconciliation aligns the platform’s flow with external systems.

4. Double‑entry bookkeeping

Each economic transaction is recorded with equal amounts in at least two related accounts using debit (借) and credit (贷) symbols. The direction (debit or credit) depends on the account’s economic nature:

Asset accounts: increase → debit, decrease → credit.

Liability accounts: increase → credit, decrease → debit.

Equity accounts: increase → credit, decrease → debit.

Cost‑expense accounts: increase → debit, decrease → credit.

Revenue accounts: increase → credit, decrease → debit.

5. Third‑party payment account system

Accounts involved include:

User bank accounts (funds source).

Third‑party payment company’s bank accounts (assets for the company).

Merchant accounts within the payment platform (liabilities for the company).

Internal total‑ledger accounts for reconciling flows.

Example accounting entry for a user paying 100 CNY via Alipay to merchant A:

Debit: Alipay’s bank account 100 CNY (asset) Credit: Merchant A’s Alipay account 100 CNY (liability)

6. Fund flow and accounting for common operations

1) User recharge 100 CNY via bank card: Debit: Payment platform’s bank account (asset) 100 CNY Credit: User’s C‑account (liability) 100 CNY

2) User pays merchant A 100 CNY: Debit: Platform’s bank account (asset) 100 CNY Credit: Merchant A’s B‑account (liability) 100 CNY

3) User withdraws 100 CNY from balance to bank card: Debit: User’s C‑account (liability) 100 CNY Credit: Platform’s bank account (asset) 100 CNY

4) C2C transfer within platform (no bank interaction): Debit: Sender’s C‑account (liability decrease) 100 CNY Credit: Receiver’s C‑account (liability increase) 100 CNY

5) B2C payment within platform (no bank interaction): Debit: Payer’s C‑account 100 CNY Credit: Merchant’s B‑account 100 CNY

Overall, third‑party payment account systems mainly involve asset and liability accounts, making the accounting relatively straightforward.