Developer productivity spans individual workflow habits, organizational systems, and AI tooling — and the sources collectively argue that output speed is the least reliable measure of it.

Engineering craft is the accumulated discipline of writing, organizing, and maintaining software well — spanning code design, tooling fluency, communication, and the judgment to know when technical excellence actually changes outcomes.

Software engineering spans craft, process, and judgment — how code is structured, tested, reviewed, deployed, and maintained — and the sources collected here collectively interrogate each layer as AI tooling reshapes who does what and why.

Systems design spans how components are structured, isolated, and coordinated to handle real-world complexity, covering tradeoffs in state management, failure recovery, module boundaries, and the diagrams used to communicate it all.