What It's Like to Work as a KakaoPay Server Developer (feat. Yeonjin, I'm So Excited Right Now)

A KakaoPay server developer needs more than just code implementation—a deep understanding of the payment and settlement domain is essential. They must build expertise as domain specialists by learning complex business rules around fees, taxes, exchange rates, and more.

Key projects include the Pay Gift Certificate and Near Me services. Pay Gift Certificate uses Kotlin, Spring MVC, MySQL, Redis, Kafka, and MongoDB to serve as a payment method and ledger. The Near Me service applies Spring WebFlux and the BFF (Backend For Frontend) pattern to asynchronously call multiple microservices.

The tech stack and environment are as follows:

• Languages and Frameworks: Java, Kotlin (primary focus for new projects), Spring (MVC, WebFlux, Batch)
• Databases and Messaging: MySQL, MongoDB, Kafka, Redis
• Infrastructure and Monitoring: k8s-based MSA, APM, Grafana, Elastic Search

Given the nature of financial services, development prioritizes security and stability above all—including development in a network-separated environment, strict transaction processing, and data masking for personal information protection.