1. Design a URL Shortener
Create short links, resolve them quickly and handle expiry without sending users to the wrong destination.
ClassicEasy
Guided practice
Start with a template. Work through each step. Ask Coach when you need a second opinion.
All designs 148
Ordered by design numberCompany tags are community-reported. Counts on cards show how many people reported that design.
2. Design a Distributed Rate Limiter
Enforce tenant quotas across servers while making burst behavior and outage policy explicit.
ClassicMedium3. Design a Distributed Cache
Partition cached data, survive node loss and keep cache misses from overwhelming the source of truth.
ClassicMedium4. Design a Notification System
Deliver email, push and SMS with preferences, retries and honest delivery status.
ClassicMedium5. Design a Chat System
Send durable messages, reconnect devices and explain ordering and delivery receipts.
ClassicMedium6. Design a News Feed
Build a paginated feed that handles high-fan-out authors, fresh posts and visibility changes.
ClassicMedium7. Design a File Storage Service
Upload and share large files with resumable transfer, versions and safe metadata changes.
ClassicMedium8. Design a Video Streaming Platform
Turn uploads into playable renditions and serve viewers through unreliable networks.
ClassicHard- Practice briefStart with your own approach
9. Design Search Autocomplete
Return useful prefix suggestions quickly while refreshing rankings and removing unsafe entries.
ClassicMedium 10. Design an API Gateway
Route API traffic with authentication, tenant limits and safe configuration rollout.
ClassicMedium11. Design a Container Orchestrator
Reconcile desired workloads, schedule containers and recover from failed nodes safely.
ClassicHard- Practice briefStart with your own approach
12. Roll out configuration to a disconnected fleet
Safely converge 40,000 gateways while some sites are disconnected and old controllers can return.
Infrastructure & SREHard - Practice briefStart with your own approach
13. Keep a regional ingress service alive
Survive a regional outage without confusing a health check with safe recovery.
Infrastructure & SREHard - Practice briefStart with your own approach
14. Sell a limited drop without overselling
Separate reservation, payment and confirmed purchase during a 50,000-person launch.
Product & backendMedium - Practice briefStart with your own approach
15. Sync inspections from offline field teams
Reconcile conflicting edits and large photo uploads without losing submitted inspections.
Product & backendMedium - Practice briefStart with your own approach
16. Migrate payment processors without a flag day
Create a gated migration plan when engineering, finance and support have different definitions of success.
Technical program managementHard - Practice briefStart with your own approach
17. Launch a regional data-residency commitment
Turn an enterprise residency promise into enforceable scope and a cross-team launch plan.
Technical program managementHard - Practice briefStart with your own approach
18. Keep enterprise AI search fresh and private
Handle document changes, ACL revocation and deletion across a retrieval pipeline.
AI systemsHard - Practice briefStart with your own approach
19. Ship a cheaper model without hiding regressions
Build a release decision from noisy evaluations, customer slices and production feedback.
Machine learningMedium - Practice briefStart with your own approach
20. Test a neighborhood tool library
Choose a useful first service before spending a small team’s budget on an app.
Product managementMedium - Practice briefStart with your own approach
21. Help workshop visitors find a reason to return
Investigate a drop in repeat visits and choose one test without assuming reminders are the answer.
Product managementMedium - Practice briefStart with your own approach
22. Make a first studio visit feel clear and welcoming
Design a complete arrival experience across booking, signs, staff and a changed room.
UX & service designMedium - Practice briefStart with your own approach
23. Explain an event change before people make the trip
Keep a community event’s update, travel and arrival experience consistent when plans change.
UX & service designMedium - Practice briefStart with your own approach
24. Organize a fair maker-market application process
Process more applications than available tables with clear decisions, ownership and a waitlist.
OperationsMedium - Practice briefStart with your own approach
25. Keep community support requests from getting lost
Make ownership and honest response promises work with a limited weekly support budget.
OperationsMedium - Practice briefStart with your own approach
26. Share one study room without double bookings
Explain a simple booking process, try it with examples and improve one weak spot.
FoundationsEasy - Practice briefStart with your own approach
27. Run a book-swap table that newcomers can understand
Arrange a small community activity with clear rules, a simple record and a closing plan.
FoundationsEasy - Practice briefStart with your own approach
28. Aggregate events that arrive late or twice
Keep tenant usage totals correct across duplicate delivery, late events, outages and replay.
Data engineeringMedium 29. Cache-Aside (Lazy Loading)
A read-heavy service sends every request to a database that is slower and more expensive per read than memory, and the same few rows are asked for over and over.
Infrastructure & SREMedium30. Transactional Outbox
A service commits to its database and then publishes an event. If it dies in between, the row exists and no one hears about it. Publishing first has the mirror problem: an event for a write that never happened. There is no ordering of two independent systems that makes this safe.
Product & backendMedium