// TOPIC
#kafka
4 articles
◆◆IntermediateMetaGoogle
01Design a Notification System (Push, Email, SMS)
A reliable multi-channel notification platform — fanout, templates, dedup, rate limiting, and the realities of APNS/FCM.
#interview#notifications#messaging
14 min◆◆◆AdvancedMetaDiscord
02Design WhatsApp / Chat System
Realtime 1:1 and group messaging at billions-of-users scale. WebSocket gateways, message store, presence, end-to-end encryption.
#interview#realtime#websocket
16 min◆◆◆AdvancedMetaTwitter
03Design Twitter / X (the home timeline)
500M users, 500M tweets/day, p99 feed loads under 200ms. The fanout-on-write vs fanout-on-read trade-off that defines the system.
#interview#feed#fanout
16 min◆◆Intermediate
04Message Queues and Event Streams
Queues vs streams, Kafka in depth, delivery semantics, idempotency, dead-letter queues, schema registries, the outbox pattern, and stream processing fundamentals.
#messaging#asynchronous#kafka
17 min