⏱ 3 min read A live leaderboard ranks users by score in real time — ranking millions of players by score in a game, […] Read article

⏱ 6 min read An ad click tracking system records every click on an advertisement, deduplicates fraudulent clicks, aggregates counts for billing, and provides Read article

⏱ 6 min read A ticketing system (like Ticketmaster for concerts, or an airline seat booking system) manages limited inventory under simultaneous high demand. Read article

⏱ 6 min read A payments system processes financial transactions — charge customers, transfer funds, process refunds. Unlike typical web applications, payments demand ACID Read article

⏱ 6 min read Real-time server-to-client communication requires the server to push data without waiting for a client request. Three primary patterns exist: long Read article

⏱ 6 min read Observability is the ability to understand the internal state of a system from its external outputs. A system is observable Read article

⏱ 5 min read Exactly-once delivery means that every message is processed precisely once — neither lost (at-least-once) nor delivered multiple times (at-most-once). True Read article

⏱ 6 min read Backpressure is a mechanism that allows a downstream component to signal an upstream component to slow down — preventing fast Read article

⏱ 6 min read The Saga pattern is a way to manage data consistency across multiple services in a microservices architecture without using distributed Read article

⏱ 6 min read Multi-tenancy is an architecture where a single application instance serves multiple customers (tenants), with each tenant’s data isolated from others. Read article

⏱ 6 min read Data archival is the systematic movement of infrequently accessed data from primary storage to cheaper, slower storage while maintaining the Read article

⏱ 6 min read A monitoring and alerting system collects metrics from distributed services, stores them efficiently, evaluates alert conditions, and notifies on-call engineers. Read article

⏱ 6 min read Load shedding is the deliberate rejection of requests when a system is overloaded — sacrificing some requests to protect the Read article

⏱ 7 min read Deleting data is irreversible by default. Soft delete marks records as deleted without removing them from the database; hard delete Read article