Reconstructing Ctrip's Payment Engine: Architecture, Design, and Operational Practices

Speaker Hong Guangming, Development Director of Ctrip's Financial Business Unit, introduces the reconstruction of Ctrip's payment backend system.

The legacy payment platform, handling millions of daily transactions and trillions of annual transaction volume, suffered from lack of unified payment flow design, missing independent accounting system, heavy reliance on stored procedures, inflexible database design, and complex inter‑service call graphs that hindered new financial product development.

The redesign splits the system into two core services: a Payment Planning service responsible for request validation, acquisition, routing, risk checks, and plan generation; and a Payment Engine service that executes plans, connects to payment channels, and notifies results. Each payment channel (bank cards, third‑party services, gift cards, wallet balance, etc.) is encapsulated in an independent service.

The new architecture is illustrated with diagrams (images omitted here) showing a clearer, simpler call relationship compared to the old system.

A dedicated settlement reconciliation system matches funds settled through multiple channels against internal accounting records, automatically processing daily reconciliation for nearly a hundred channels, improving operational efficiency and ensuring fund safety.

To meet high stability requirements, Ctrip monitors payment availability (ATP) and improves it through architectural choices (order‑payment separation, asynchronous processing with automatic retries), technical measures (distributed services, high‑availability design, eliminating single points of failure), and operational practices (comprehensive monitoring, alerting, and rapid incident response).

The talk concludes with an overview of the payment engine reconstruction project.