CrackingWalnuts
New
We’re on YouTube too
Now we also crack a few walnuts out loud, on video. Everything here stays right where it is.
More than interview prep. Your path forks at Senior, into building (IC) or leading (management). Pick a goal, see the real bar, and follow the exact path to get there.
Built by Staff Engineers, Principal Engineers, and Engineering Leaders who've built systems, led teams, and hired engineers.
The bar for each level is the real one, not generic advice.
Question: Your cache contains the correct value. The application returns an older one. How can a cache hit return stale data from somewhere else?
Have your answer in mind, then reveal.
Pick a level and be honest. Could you actually answer each of these out loud, right now? If several are shaky, that is the gap, and that is exactly what the path is for.
The bar: Design across services, make and defend trade-offs, and lead a design review.
If several are shaky, you are probably not there yet. Here is the path.
See the Senior Engineer pathWhether you are building LLM systems or getting grilled on them, go deep: the foundations, the engineering, the security, and the AI system design round. Read a full lesson free before you decide.
Design a distributed rate limiter for 1M decisions a second. Eight algorithms with worked examples, tested Valkey Lua scripts, how to set up the Valkey cluster, a rule engine, what happens when each part goes down, bottlenecks, analytics, cost, and what breaks at 10x and 100x.
