My notes on system design and data engineering.
In interviews I've watched everyone, senior and junior, get stuck on the same two topics: system design and real production data engineering. I wanted a clearer way through, so I started writing this. A six-month roadmap, plain-English answers to 268 core concepts, and 122 hands-on practice problems. All free, updated regularly. Worth a bookmark.
Pick a roadmap.
Six months, in order.
Don't know where to start? The roadmaps are the on-ramp. Each one is seven stages from beginner to senior. You finish each stage by building something small, not by collecting certificates.
System Design
PracticeInterview-style design questions with senior-level follow-ups.
Data Engineering
PracticeReal production scenarios from pipelines that actually break.
268 answers in plain English.
Pick a library.
Short, opinionated explainers across system design, data engineering, and the Swedish energy market. Built for fast lookups during interview prep or a design review.
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WritingCareer notes, mental health in tech, and the engineering lessons that took me years to learn.