Operating a Notification System with BullMQ, Part 1: What Is BullMQ?
Sending AlimTalk, email, and push as HTTP calls hits limits fast. Why BullMQ takes on rate limits, scheduling, and delivery history.
Blog
Why Kubernetes Kills My Pod: Health Probes
Kubernetes judges a Pod with liveness and readiness probes: when each restarts a container or holds back traffic, Spring and NestJS setup, and pitfalls.
2025 Retrospective
Clean code, refactoring, TDD, and DDD felt like enough. The AI era showed that writing code well no longer creates irreplaceable value. A 2025 retrospective.
Reducing CDN Costs with Browser Caching
Browser cache settings alone cut more than a million won a year of CDN cost. How a CDN works, and which Cache-Control header keeps responses in the browser.
A Ticketing System That Can Theoretically Handle 100,000 QPS
The first 1,000 tickets go through a web app behind a distributed lock. Does that lock actually keep concurrency under control when the rush hits?