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• Design an AI Code Review Bot: PR Comments, Noise and CostAI and GenAI · A plain-English guide to AI code review system design: how a bot reads pull requests, cuts false positives and keeps cost per review low, shown on one running example of a review bot sold to software teams.25 min read · Updated 24 Oct 2026
• API Gateway vs BFF: One Shared Front Door or One Backend for Each AppBackend · A plain-English guide to API gateways and the backend-for-frontend pattern: what each layer does, how they differ and when you need both, shown on one running grocery app example.19 min read · Updated 24 Oct 2026
• Autoscaling Explained: Scale on the Right SignalBackend · A plain-English guide to autoscaling: how the scaling loop works, which metric to pick, how to beat spikes and stop flapping, shown on one running example of a flash-sale checkout.27 min read · Updated 24 Oct 2026
• The 2017 AWS S3 Outage Explained: One Typo, Four HoursSystem design · A plain-English guide to the 2017 AWS S3 outage: the mistyped command, why it spread, why recovery was slow and what AWS changed, shown on one running example of an online print shop.23 min read · Updated 24 Oct 2026
• Backpressure Explained: Slowing Producers Before Queues ExplodeSystem design · A plain-English guide to backpressure: why queues blow up when producers outrun consumers, and how bounded queues, pull, load shedding and 429s fix it, built on one running SMS gateway example.20 min read · Updated 24 Oct 2026
• Batch vs Stream Processing Explained: Late Data, Lambda and KappaSystem design · A plain-English guide to batch vs stream processing: daily jobs, live windows, late data and watermarks, and the Lambda and Kappa architectures, shown on one running example of a rooftop-solar monitoring service.25 min read · Updated 24 Oct 2026
• Blob Storage Design: How an S3-Style Store Keeps Files SafeSystem design · A plain-English guide to blob storage design: chunks, metadata, copies, erasure coding and repair, shown on one running example of a team storing 400 TB of customer files.25 min read · Updated 24 Oct 2026
• Calendar System Design: Recurring Events and Time ZonesSystem design · A plain-English guide to calendar system design: recurring events as rules, exceptions, time zones, daylight saving, reminders and week views, shown on one running example of a weekly family video call.24 min read · Updated 24 Oct 2026
• Cassandra Consistency Explained: Levels, Quorums and RepairSystem design · A plain-English guide to Cassandra consistency levels, how reads and writes wait for replicas, and how to pick a level per query, built on one running farm-sensor example.19 min read · Updated 24 Oct 2026
• Clock Synchronization Explained: Why Server Timestamps Lie and What to DoSystem design · A plain-English guide to clock synchronization: why server clocks drift, how NTP corrects them, why timestamps still lie, and what TrueTime does, built on one running cardamom auction example.26 min read · Updated 24 Oct 2026
• Design Google Docs: OT vs CRDTsSystem design · A plain-English guide to collaborative editing that compares operational transformation and CRDTs, shown on one running example of a small-team document editor.20 min read · Updated 24 Oct 2026
• Core Web Vitals Explained: LCP, INP and CLS With Real FixesFrontend · A plain-English guide to Core Web Vitals: what LCP, INP and CLS measure, the good lines, and the fixes that move each one, shown on one running example of an online jewellery store's product page.28 min read · Updated 24 Oct 2026
• CPU vs GPU vs TPU for AI: Which Chip for Which JobAI and GenAI · A plain-English guide to choosing between CPUs, GPUs and TPUs for training, inference and embeddings, shown on one running example of an Indian-language search team.26 min read · Updated 24 Oct 2026
• Disaster Recovery: RTO, RPO and Multi-Region PlanningBackend · A plain-English guide to disaster recovery, from RTO and RPO to backups, warm standby and region failover, built on one running pension-records example.26 min read · Updated 24 Oct 2026
• Event Sourcing and CDC: Store Events, Derive StateSystem design · A plain-English guide to event sourcing, change data capture and the outbox pattern, built on one running example of a prepaid society wallet in Ahmedabad.26 min read · Updated 24 Oct 2026
• The 2021 Facebook Outage Explained: BGP and DNSSystem design · A plain-English guide to the 2021 Facebook outage, from the backbone command and the BGP withdrawals to the DNS loss and the slow recovery, shown on one running example of a regional internet provider.19 min read · Updated 24 Oct 2026
• Fallacies of Distributed Computing: Crash, Omission, ByzantineSystem design · A plain-English guide to the eight fallacies of distributed computing and the failure models behind them, built on one running drone fleet example.20 min read · Updated 24 Oct 2026
• Design Dropbox or Google Drive: File Sync System DesignSystem design · A plain-English guide to file sync system design: chunking, uploads, change journals, conflicts and storage maths, shown on one running example of a shared office folder.26 min read · Updated 24 Oct 2026
• Design a Food Delivery App: Orders, Riders and PaymentsSystem design · A plain-English guide to food delivery system design: order states, payments that never charge twice, rider dispatch, live tracking and the dinner rush, shown on one running example of a city food delivery app.30 min read · Updated 24 Oct 2026
• Frontend State Management at Scale: Server State vs UI StateFrontend · A plain-English guide to frontend state management at scale: server state, UI state, URL state, caches and stores, built on one running seller dashboard example.25 min read · Updated 24 Oct 2026
• Frontend System Design Interview: A Five-Step FrameworkFrontend · A plain-English guide to the frontend system design interview: a five-step framework from requirements to speed and accessibility, shown on one running example of a shopping search page.28 min read · Updated 24 Oct 2026
• Grouped Query Attention Explained: How GQA Shrinks the KV CacheAI and GenAI · A plain-English guide to grouped query attention: how multi-head, GQA and multi-query attention change memory use, speed and quality, shown on one running long-document chat example.22 min read · Updated 24 Oct 2026
• HTTP/1.1 vs HTTP/2 vs HTTP/3: What Each Version FixedBackend · A plain-English guide to HTTP/1.1, HTTP/2 and HTTP/3: what each version fixed, what one lost packet costs, and which to use, shown on one running example of a comics reading app.23 min read · Updated 24 Oct 2026
• How Kafka Works Internally: Log, Partitions and ReplicasSystem design · A plain-English tour of Kafka internals: the log, partitions, offsets, replicas, broker failure and consumer groups, built on one running bus telematics example.22 min read · Updated 24 Oct 2026