Building a Delayed Transfer Service: Implementing Automatic Transfers After Bank Maintenance Ends (feat. Presentation Recap)

Kakao Pay's delayed transfer service is a feature that schedules transfers during bank maintenance hours and automatically executes them once maintenance ends. The existing system operated on a delay-queue-based architecture using RabbitMQ.

As the company's standard message queue was consolidated to Kafka, the team faced the challenge of redesigning the architecture without service interruption. In the initial stage, they reviewed a scheduler approach that ran every 5 minutes, but this showed clear performance limitations for processing thousands of transfers in a short time.

They also considered using multiple schedulers, but this was flagged as limited due to issues with duplicate processing prevention and infrastructure complexity. In the end, they designed a new architecture based on Kafka, solving the problem by improving processing speed by more than 8x compared to before.