How We Maintain a Monorepo, and Why DLL Boundaries Matter More

The company I run fundamentally adopts a Monorepo approach. Our folder structure is therefore not designed to "make the code look neat," but rather based on how we manage dependencies and reuse code properly. Many people debate whether to organize by feature or by domain. I approach this from a slightly different perspective.

The Repeating 3-Week Pattern: What I Learned by Finishing the Last Course Myself

POCU video lectures come with transcripts that someone already cleaned up once. The content is mostly accurate, but the line breaks and punctuation are all over the place. To use them in an automated pipeline, they need to be reorganized. One student had been helping me with that work for several years on a part-time basis. He worked on multiple courses, and strangely, the pattern was always the same.

Old New Music: How Can I Make You Leave Her?

I realized I never shared this song on my blog. It's a track I released on April Fool's Day back in 2015. The title is "How Can I Make You Leave Her?"

Stripe, KRW Local Payments, and the Never-Ending DCC Problem

Every time you pay on an overseas website, you've probably seen that little popup asking if you'd like to pay in KRW or USD. That's DCC — Dynamic Currency Conversion. It sounds convenient, but in reality it almost always costs you more. The merchant or payment processor uses its own exchange rate and adds a markup on top. So, in most cases, it's much cheaper to just pay in the local currency (USD, EUR, etc.). Paying in KRW on a foreign site basically means paying extra for nothing.

AWS Went Down? Multi-Cloud Isn't the Answer

Over the past few days, many people have lost their illusion of "safety." On October 20 (local time), AWS's US-EAST-1 region suffered a massive outage. Countless apps and services went down one after another. The cause was traced to DNS resolution failures and issues that originated in internal subsystems and data layers (such as EC2 and DynamoDB APIs). Social media, gaming, productivity tools—even parts of government and education systems—were shaken. It took nearly an entire day to recover, and the ripple effects lingered.

Rust Is a Great Language — But It's Not a Religion

Ten years ago, when no one cared, I was already saying it: "Rust is a great language." Back then, I had no data to back it up. It was just my gut feeling and experience. Rust was designed in a way that naturally prevents programmers from making common mistakes.

How to Minimize Side Effects When Writing to Two Databases at the Same Time

Normally, data is stored in a single database. However, sometimes you may need to write to two physically separate DB servers at the same time.

Five Defensive Utility Functions I Made

🎯 Introduction

Engineering in Plain Sight Review: A New Way of Seeing the World

One day, while browsing the shelves at the library, I stumbled upon a book that caught my eye. The title was Engineering in Plain Sight (by Grady Hillhouse). Honestly, at first I just thought the illustrations were pretty, and the first few pages looked fun, so I picked it up lightly, assuming it was just some kind of illustrated reference book.

In an Era of Frequent Facebook Graph API Deprecations, This Is How You Manage ASP.NET Core Login

Adding Facebook login to ASP.NET Core is supposed to be really simple. Just install the Microsoft.AspNetCore.Authentication.Facebook NuGet package, call services.AddFacebook(), set the AppId and Secret, and you're done. The login screen appears, and tokens come back as expected.