Sharing notes on backend architecture, data engineering, and product-aware system design — based on my experiences and research.
Apr 10, 2026
ETL and ELT share the same three letters in a different order. That difference drove a fundamental shift in how modern data teams build their stacks. This post explains what changed, why ELT won, and where ETL still holds ground.
Apr 07, 2026
Mainframes handle 70% of the world's production IT workloads. Most engineers have never seen one. Here is what they are, how they work, and why they are still running.
Mar 31, 2026
Backend systems are complex, with components acting at different layers. We start simple: one machine running everything. Understanding this baseline is the foundation for everything that follows.
Mar 30, 2026
Dependency injection is not dependency inversion. One tells you how to pass dependencies. The other tells you who gets to define their shape. Here's the distinction, built from first principles.
Mar 29, 2026
AI tools are everywhere, but access isn't fluency. This post introduces the 4D AI Fluency Framework: a durable set of thinking skills for working with AI effectively, efficiently, ethically, and safely.
Mar 25, 2026
A high-level walkthrough of the architecture behind a hotel reservation system: the read/write split, concurrency traps, and why it's never just CRUD.