Drawing a cache is easy. Explaining why it helps is where interviews are won. Why we built Basis Lab, an AI tutor for the fundamentals under system design, with a worked caching example and the free courses that map to interview topics.

By Codemia • Oct 9, 2026

6 min read

Behind the scenes of Codemia's whiteboard explainer videos: why we built openCanviz, how a 21 minute system design video goes from a blog post to a narrated export, and the rules we learned about putting numbers and ideas on screen.

By Codemia • Oct 9, 2026

7 min read

How to design a Prometheus or Datadog style monitoring system in an interview: requirements, capacity math for 5 million samples per second, push versus pull collection, time series storage and compression, downsampling, cardinality, and an alerting pipeline that does not page people at 3am for nothing.

By Codemia • Oct 8, 2026

13 min read

A complete answer to "design an elevator system": requirements, the car state machine, SCAN and LOOK scheduling, multi-car dispatch with a cost function, destination dispatch, emergency modes, failure handling, and what the interviewer is listening for.

By Codemia • Oct 8, 2026

14 min read