Concept by concept: what each piece is, the problem it solves, and a hands-on build — then apply everything in a mock interview.
0 of 12 concepts completed
What a load balancer is, how it spreads traffic, and why it buys you reliability — not just capacity.
~10 min
What a cache is, hits vs misses vs TTL, where caches live, and when NOT to use one.
~10 min
Doing slow work later so users never wait on it.
~9 min
Serving files from close to the user instead of across the planet.
~8 min
Tables vs documents, indexes, and what a database is actually good at.
~11 min
Copying data for safety and splitting it for scale.
~11 min
Where the photos, videos and files actually live.
~7 min
What "eventually consistent" really means, without the theory pain.
~10 min
Ready to be tested?
The interview simulator runs you through requirements, estimation, API design, the architecture canvas and deep-dive questions — with an AI interviewer.