Four libraries,one account
Each course is a library rather than a syllabus, so you can start two weeks before a loop and still use it properly. Every course keeps a permanent free sample — complete items, not previews.
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WinSystemDesign
Distributed systems, end to end
Design the systems interviewers actually ask about. Every question is a full walkthrough: requirements, estimates with the arithmetic shown, the architecture component by component, the trade-offs, and the follow-ups.
WinAI
AI and ML interviews
Model serving, retrieval, evaluation and the system design around them, with quizzes and spaced-recall decks over the same material.
Also available
WinCloud
Cloud architecture
Architecture across the major providers: the patterns, the trade-offs between managed and self-run, and the questions cloud-heavy loops open with.
WinOps
Running production
The half of seniority that is not whiteboard design: incident response, on-call, runbooks and the compliance work that comes with owning a system.