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SYSTEM DESIGNDesign a Pub/Sub SystemGoogleAWSRabbitMQ
TRAFFIC LEVEL
—/3
CONSTRAINTS
Messages/sec1,000,000
Topics100,000
Subscribers/topic1-1000
Message retention7 days
Delivery guaranteeAt-least-once
Compute & Network
Load BalancerDistribute traffic
API GatewayEntry point / auth
API ServerBusiness logic
Worker NodeAsync processing
CDN EdgeGlobal cache
WebSocket GatewayPersistent connections
Data Stores
PostgreSQLRelational DB
MySQLRelational DB
CassandraWide-Column DB
DynamoDBNoSQL / Managed
S3 BucketObject storage
Queues & Cache
Redis CacheIn-memory store
KafkaEvent stream
ZookeeperCoordination
Specialized
Bloom FilterProbabilistic set
Rate LimiterThrottling
Geohash ServiceGeospatial index
Trie ServerPrefix search
APNS / FCMPush notifications
AggregatorBatch / roll-up
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GoogleAWSRabbitMQ

Design a publish-subscribe messaging system. Publishers send messages to topics without knowing the subscribers. Subscribers declare interest in topics and receive all messages. Support at-least-once delivery, 1M messages/sec throughput, and message retention for 7 days (so a subscriber can catch up after being offline).

📥 Assigned to:You — Mid Engineer
SCALE LEVELS
1
10,000 RPS
Target: <10ms
2
100,000 RPS
Target: <50ms
3
1,000,000 RPS
Target: <20ms
GLOBAL SUCCESS RATE
100.0%
P99 LATENCY
45ms
Target: < 200ms
TOTAL RPS INGESTED0 / 11,000
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