Mock Rounds
Timed practice under interview conditions. The Interview Simulator runs a full 45 minute system design round phase by phase, with interviewer follow-ups and a checklist for your level. The Mixed Timed Drill runs a set of cards from several rounds on the clock.
Matching Mock
Interview Simulator
A full system design round in 45 minutes, graded at your level.
- Design a URL ShortenerJunior
- Design a Rate LimiterMid
- Design a News FeedSenior
- Design a Multi-Region Payments LedgerStaff
- Design a Cell-Based ArchitecturePrincipal
Drill Types
Read These First
All Learn PagesCommon Mistakes
Pausing the clock
Real interviews don't stop. Finish the round, then read the report.
Revealing too early
A revealed phase doesn't count as earned. Attempt each phase before you reveal it.
Skipping the report
It names the two gaps to drill next.
All Simulators
Interview Simulator
A full system design round in 45 minutes, graded at your level.
Staff