Design Twitter / X home feed
A complete 45-minute mock covering write fanout, celebrity carve-out, and feed storage.
First win
You can defend push vs. pull vs. hybrid fanout with concrete thresholds.
Best for
Engineers prepping for FAANG system design interviews
Needs
Mac, Microphone, Whiteboard tool (Excalidraw, Figma, etc.)
Example outcome
A social feed becomes a full 45-minute mock.
This preview shows the interview shape: requirements, API, and the push / pull / hybrid fanout deep dive walked with concrete thresholds.
Mock interview
Phases hit
6
Requirements, core entities, API, high-level design, deep dives, and wrap-up walked end-to-end with concrete numbers.
Deep dives
Two or three subsystems
You drive the most interesting tradeoffs unprompted with sub-100ms numbers when needed.
Wrap-up
You name what you optimized for and what you gave up out loud.