Nodivex

System design katas

A kata is a focused practice scenario. You get a brief with real constraints, sketch an architecture, run a simulation, and see what holds. Each kata trains a different aspect of system design thinking.

Try a kata

Coffee please

Retail technology · 20–35 min

Beginner

Business goals

  • Prevent double-charges under retries
  • Keep checkout responsive during peak rush

Constraints

  • Flaky payment provider
  • No manual steps
  • No signup required
  • Start in under 2 minutes
  • Feedback from simulation data
What is a system design kata

A repeatable exercise that turns system design into a testable skill

In martial arts, a kata is a sequence you practise until it becomes second nature. A system design kata works the same way: you receive a scenario with requirements and constraints, design a system to meet them, and get immediate feedback on what works and what breaks. Each repetition sharpens your judgment on trade-offs between latency, cost, reliability, and operability.

Kata library

Pick a kata and start practising

Each kata is a self-contained scenario. Open one, sketch a system, and see how it handles the constraints.

  1. 01Big news on campusServe a sudden surge of reads when thousands of users open the same notification at once.Education TechnologyBeginner–Intermediate · 20–35 min
  2. 02The waiting roomGive patients a fast booking acknowledgement while processing confirmations asynchronously.HealthcareIntermediate · 25–40 min
  3. 03Checkout with change feedsSeparate transactional order writes from analytical reads using change feeds and read replicas.E-commerceIntermediate–Advanced · 30–45 min
  4. 04The flash saleKeep checkout stable during a scheduled surge using admission control and queue buffering.E-commerceIntermediate · 25–40 min
  5. 05The multi-writerManage four competing actors writing to a shared database without contention degrading any single channel.LogisticsAdvanced · 35–45 min
  6. 06Legacy lifelineProtect a fixed-capacity legacy system from modern traffic volumes without replacing it.Financial ServicesIntermediate · 25–40 min
  7. 07The meal dealSize a food-ordering backend to survive the lunch rush without blowing the budget.Food DeliveryBeginner · 20–30 min
  8. 08Match day scoresServe live sports scores to a massive audience using layered caching without overwhelming the origin.Sports MediaBeginner–Intermediate · 20–35 min
  9. 09Coffee pleasePrevent double-charges and duplicate orders during peak demand and retries.Retail TechnologyBeginner–Intermediate · 20–35 min
  10. 10Three screens, one backendServe web, mobile, and in-store kiosk from shared infrastructure without one channel degrading another.RetailIntermediate · 25–40 min
  11. 11Payment handshakeProcess payments through an external gateway with tight error tolerance and async settlement.FintechAdvanced · 35–45 min
  12. 12The status dashboardServe millions of status page reads during an incident using layered caching and read path isolation.SaaS / DevOpsIntermediate–Advanced · 30–45 min
  13. 13The event feedPublish events once and fan out to multiple subscribers without the slowest one dragging down the publisher.Social / Content PlatformIntermediate · 25–40 min
  14. 14Ticket DropKeep checkout stable during an on-sale surge when a dependency partially fails.Consumer InternetIntermediate · 25–40 min
Try a kata
Nodivex

Pick a kata and see what your design can handle

Open a scenario, sketch a system, and let the simulation show you the trade-offs.

Try a kataLearn about system design