Fundamentals

This track is the heart of Code of the Day. While syntax changes and tools come and go, the ideas here stay true: how programs actually work, how to read documentation and unfamiliar code, how to think in systems, and how to get real leverage from AI coding agents without losing your own judgement.

Two tiers

• Beginner — Mental Models: the foundational ideas every programmer relies on, whether they realise it or not.
• Intermediate — Systems & Structure: how to reason about whole systems, architecture, performance, and verification.

Pick a tier from the sidebar to begin.