fanout
2 pages tagged fanout.
System Design
004hard
Chat System
Designing a real-time messaging system end to end — persistent connections and session routing, per-conversation ordering, at-least-once delivery with client dedupe, offline push, multi-device sync, presence, and where end-to-end encryption changes the architecture.
005medium
Notification Service
Designing a multi-channel notification system end to end — accept-then-deliver queues, the eligibility pipeline that decides whether to send at all, template rendering, provider quotas and failover, retries without duplicates, bounce and suppression handling, and digesting.