Distributed Notification System
Cross-channel deduplication, provider failover, quiet hours across time zones, priority lanes so OTPs never queue behind marketing, and 100M-user broadcasts.
Cross-channel deduplication, provider failover, quiet hours across time zones, priority lanes so OTPs never queue behind marketing, and 100M-user broadcasts.
Token bucket vs sliding window, atomic Lua enforcement, cross-region drift, fail-open policy, and the hot tenant that melts one Redis shard.