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Frontend System Design — Core 5
Walk into the room ready — not with memorized diagrams, but with a repeatable way to design real product surfaces under interview pressure.
Frontend system design rounds rarely ask you to invent a brand-new product. They ask whether you can own latency, consistency, state, and failure while the UI stays usable. These five problems are the core set that interviewers keep returning to — and the set that transfers to almost any follow-up prompt.
Why these 5 matter
Start here if you want maximum signal per hour of practice.
| # | Problem | Why interviewers love it | Skills you walk out with |
|---|---|---|---|
| 01 | Autocomplete / Search | Typeahead exists in every serious product | Debounce · race conditions · caching · accessible combobox |
| 02 | News Feed | Infinite lists are the default modern UX | Pagination · virtualization · optimistic UI |
| 03 | E-commerce Platform | Money and inventory punish weak state design | Cart ownership · checkout safety · catalog performance |
| 04 | Real-time Chat | Live systems separate mid-level from senior | WebSockets · ordering · reconnect · presence |
| 05 | Collaborative Editor | Concurrent edits expose true sync depth | OT / CRDT · convergence · offline merge |
Nail these five and a “notification center,” “kanban board,” or “docs app” stops feeling new — you already know which pattern to reach for.
How to use this track
Each chapter follows the same interview-ready flow:
Question → Requirements → Solution → Key Decisions → Q&A
- Read the prompt cold and sketch requirements first.
- Walk the solution as if you are at the whiteboard.
- Use Key Decisions and Q&A as your closer — that is where senior signal lives.
Open 01 when you are ready. Build upward in difficulty; finish with chat and the collaborative editor when you want staff-level depth.