Architecture excerpt
1. Design a URL Shortener
Create short links, resolve them quickly and handle expiry without sending users to the wrong destination.
ClassicEasy
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Ordered by design numberCompany tags are community-reported. Counts on cards show how many people reported that design.
- Architecture excerpt
2. Design a Distributed Rate Limiter
Enforce tenant quotas across servers while making burst behavior and outage policy explicit.
ClassicMedium - Architecture excerpt
3. Design a Distributed Cache
Partition cached data, survive node loss and keep cache misses from overwhelming the source of truth.
ClassicMedium - Architecture excerpt
4. Design a Notification System
Deliver email, push and SMS with preferences, retries and honest delivery status.
ClassicMedium - Architecture excerpt
5. Design a Chat System
Send durable messages, reconnect devices and explain ordering and delivery receipts.
ClassicMedium - Architecture excerpt
6. Design a News Feed
Build a paginated feed that handles high-fan-out authors, fresh posts and visibility changes.
ClassicMedium - Architecture excerpt
7. Design a File Storage Service
Upload and share large files with resumable transfer, versions and safe metadata changes.
ClassicMedium - Architecture excerpt
8. 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 - Architecture excerpt
10. Design an API Gateway
Route API traffic with authentication, tenant limits and safe configuration rollout.
ClassicMedium - Architecture excerpt
11. 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 - Architecture excerpt
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 & SREMedium - Architecture excerpt
30. 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