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Classic designs 39

Ordered by design number

Company tags are community-reported. Counts on cards show how many people reported that design.

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85. Design a Change Data Capture Pipeline
Every committed change in Aurora and DynamoDB, read from the log and delivered in order per row to search, caches, Redshift and an S3 lake.
ClassicMedium
Queues Databases Streaming
+8
Transactions Distributed systems AWS Change data capture Debezium Kafka Outbox PostgreSQL
Worked design
Practice
88. Design a Reviews and Ratings System
Dish reviews only from customers who ordered them, votes counted from a change stream, reviews ranked by the Wilson bound, payouts made exactly once.
ClassicMedium
Databases Streaming Distributed systems
+7
AWS DynamoDB Kafka Ranking Ratings Reviews Social
Worked design
Practice
89. Design a Donations Website for a Charity Event
Ten charities, three days, $100 M: charge through a third-party processor exactly once, queue the broadcast spikes, keep live totals on sharded counters. One-hour boards for junior, senior and staff, with the theory behind them.
ClassicMedium
Sharding Queues Databases
+6
Distributed systems AWS DynamoDB Idempotency Payments Reconciliation
Worked design
Practice
90. Design a Book Seller Aggregator Platform
Buy the cheapest offer under a maximum price from 1,000 sellers: cached offers, coalesced quotes, a hold-order-capture saga, open requests.
ClassicMedium
Caching Databases AWS
+5
Booking DynamoDB Marketplace Payments Sagas
Worked design
Practice
92. Design Online Chess
Real-time rated chess with server-validated moves, lag-compensated clocks, pairing by rating and a million watchers on one game.
ClassicMedium
Databases AWS DynamoDB
+4
Gaming Matchmaking Ratings WebSockets
Worked design
Practice
93. Design a Real-Time Game Leaderboard
Rank 200 million players in real time with sharded Redis sorted sets, count every game exactly once, and close a season fairly.
ClassicMedium
Caching Databases Streaming
+8
Distributed systems AWS Flink Gaming Kafka Leaderboards Redis Sorted sets
Worked design
Practice
95. Design a Team Chat App like Slack
Design a team chat app like Slack: channels and DMs in real time, threads, unread counts and search. One-hour boards for junior, senior and staff, with the theory behind them.
ClassicMedium
Databases Search AWS
+5
DynamoDB Fan out Messaging Real time WebSockets
Worked design
Practice
99. Design a Cross-Product Tagging System
One set of tags across Jira issues, Confluence pages and Bitbucket pull requests: batch renders, tag pages that never leak, suggestions, popular tags.
ClassicMedium
Databases Search Security
+6
AWS Collaboration DynamoDB Many to many OpenSearch Permissions
Worked design
Practice
100. Design a Distributed File System
Billions of files, hundreds of petabytes, one strongly consistent tree: a namespace partitioned by directory, chunk servers, replication, repair, erasure coding. One-hour boards for junior, senior and staff, with the theory behind them.
ClassicMedium
Databases Distributed systems AWS
+6
DynamoDB Erasure coding File system Infrastructure Replication Storage
Worked design
Practice

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Classic designs 39

85. Design a Change Data Capture Pipeline

88. Design a Reviews and Ratings System

89. Design a Donations Website for a Charity Event

90. Design a Book Seller Aggregator Platform

92. Design Online Chess

93. Design a Real-Time Game Leaderboard

95. Design a Team Chat App like Slack

99. Design a Cross-Product Tagging System

100. Design a Distributed File System