Hello!
I’m Jeongil Jeong, Backend Developer
Sharing my development journey through honest documentation of challenges faced, solutions found, and lessons learned. Thank you for visiting.
Main Sections
Blog
Recording problems I’ve encountered, solutions, and learning experiences
Documentation
Documenting development rules and references
About Me
Introducing my journey as a backend developer and tech stack
Recent Posts
Surviving as a Non-CS Developer: A 3-Year Retrospective
Hello. I’m Jeongil Jeong, a backend developer with three years of experience, currently working at a proptech startup. Thinking of people wondering whether to start development as a non-CS major, I’ve...
June 18, 2026
How Does a Service Earn Its Users' Trust — Treating Reliability as a Promise, Not a Gut Feeling
Hi, I’m Jeongil Jeong, a backend developer working at a proptech platform. This post is less about code or a specific technology, and more about a question that wouldn’t leave my head for a while. “Ho...
May 27, 2026
My Experience Passing the ISTQB CTFL (Certified Tester Foundation Level) Exam
Introduction Hi, I’m Jeongil Jeong, a backend developer with 3 years of experience. I recently passed the ISTQB Certified Tester Foundation Level (CTFL) certification, and I’d like to share my experie...
April 29, 2026
Building an AI Property Recommendation System — How We Handle 'Recommend me a new apartment near Gangnam Station, around 30 pyeong'
Hi, I’m Jeongil Jeong, a backend developer at a proptech platform. It seems like many companies these days are thinking hard about how to integrate AI into their services in ways that deliver real val...
March 25, 2026
API Performance P95 7s → 0.1s Backend Optimization — Finding the Bottleneck Was Harder Than Fixing It
Hi, I’m Jeongil Jeong, a backend developer working at a proptech platform. One day, as usual, I was checking the Grafana dashboard for monitoring. The average response times were mostly within a few h...
March 4, 2026