❯ arena · learn by playing
Arena.
A daily challenge, weekly leagues and quick games, all built from the course. Every answer you get right here is something you'll get right in an interview.
level–
daily streak–best 0d
this week–local pts · guest
leagueL1Intern1,421 questions in the bank
daily challengeresets 00:00 IST
5 questions.
20 seconds each.
Same five for everyone today, drawn from every quick check and trial in the course. Faster right answers score more.
this weekfull board →
level–
daily streak–best 0d
this week–local pts · guest
leagueL1Intern1,421 questions in the bank
Arena games
60–90 second rounds. Best scores stay in this browser.- arena · 90s+40 xpLatency LadderOrder the numbers every engineer should know, L1 cache to a cross-continent round trip.
- arena · 75s+40 xpPick the StoreA use case drops in. Send it to the datastore that fits before the clock runs out.
- arena · 75s+40 xpFix the OutageSymptom on the left, pattern on the right. Name the fix that stops the bleeding.
Playground
The Engineering Playground, mapped to the lessons.- playground+60 xpCache or MissBeat LRU at eviction.
- playground+60 xpHash RingAdd a node, move the fewest keys.
- playground+60 xpTrip the BreakerYou can't see the service while it's open.taught inW02 · Day 3 · Circuit breakers
- playground+60 xpBack of the EnvelopeEstimate WhatsApp-scale in seconds.
- playground+60 xpRace ConditionDouble-book a seat, then fix it.
- playground+60 xpIncident CommanderThe pager just went off.