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• The Knight Capital Glitch Explained: Dead Code and a Bad DeploySystem design · A plain-English walk through the 2012 Knight Capital glitch: the missed server, the reused flag, the rollback that made it worse and the lessons, shown on one running example of a trading team's release.18 min read · Updated 24 Oct 2026
• Kubernetes Architecture Explained: Control Plane, Nodes and PodsBackend · A plain-English guide to Kubernetes architecture: the control plane, worker nodes and pods, how a deploy flows and how a cluster heals, shown on one running example of an audiobook app.26 min read · Updated 24 Oct 2026
• Design a Live Cricket Score System That Survives an IPL FinalSystem design · A plain-English guide to live score system design: how one ball update reaches millions of phones in about a second, built on one running cricket app example.20 min read · Updated 24 Oct 2026
• Buying an LLM Service: Vendor Due-Diligence ChecklistAI and GenAI · A plain-English guide to LLM vendor evaluation: data retention, training use, who owns what, lock-in and a tested exit plan, shown on one running example of a hospital drafting discharge summaries.23 min read · Updated 24 Oct 2026
• MCP in Production: Multi-Server Setups, Auth and LoggingAI and GenAI · A plain-English guide to running MCP in production: shared servers over Streamable HTTP, tokens bound to one server, and traces across every tool call, shown on one running example of a company assistant with many tool servers.25 min read · Updated 24 Oct 2026
• MCP Security: Tool Poisoning, Elicitation and Server TrustAI and GenAI · A plain-English guide to MCP security: tool poisoning, rug pulls, tool shadowing, unsafe elicitation and how a client decides which servers to trust, shown on one running example of an AI assistant for financial advisers.26 min read · Updated 24 Oct 2026
• Design a Distributed Monitoring System: Metrics and AlertsSystem design · A plain-English guide to monitoring system design: collecting metrics from thousands of servers, storing them cheaply and sending alerts people trust, shown on one running hosting example.28 min read · Updated 24 Oct 2026
• Design a News Feed Frontend: Virtualized Lists, Likes, CachingFrontend · A plain-English guide to the UI layer of a news feed: virtualized lists, infinite scroll, optimistic likes and client caching, built on one running community app example.27 min read · Updated 24 Oct 2026
• NIST AI RMF in Practice: Govern, Map, Measure, ManageAI and GenAI · A plain-English guide to the NIST AI RMF that turns its four functions into a worksheet for one AI feature, using one running hospital X-ray example.23 min read · Updated 24 Oct 2026
• Optimistic vs Pessimistic Locking: Version Numbers vs LocksSystem design · A plain-English guide to optimistic and pessimistic concurrency control, version checks, row locks and when to use each, built on one running pharmacy inventory example.28 min read · Updated 24 Oct 2026
• Orchestration vs Choreography: Who Runs Your Microservices?System design · A plain-English guide to orchestration and choreography in microservices: how each runs a saga, handles failed steps and crashes, and when to mix them, shown on one running example of a vet booking app.19 min read · Updated 24 Oct 2026
• Design an OTT Streaming Platform for Live SportSystem design · A plain-English guide to OTT system design for live sport: segments, playlists, CDN caching and plans for match-day spikes, shown on one running example of a sports streaming app in India.25 min read · Updated 24 Oct 2026
• Payment System Design: Ledgers, Idempotency and ReconciliationSystem design · A plain-English guide to payment system design: double-entry ledgers, duplicate-proof payments, pending UPI payments, reconciliation and settlement, shown on one running example of a UPI QR payments company.25 min read · Updated 24 Oct 2026
• Design a Quick-Commerce App (10-Minute Delivery)System design · A plain-English guide to designing a 10-minute grocery app, from dark stores and live per-store stock to safe holds and restocking, built on one running Delhi example.20 min read · Updated 24 Oct 2026
• Design a Ticket Booking System: Seat Locks and Flash SalesSystem design · A plain-English guide to designing a movie and concert ticket booking system, from seat holds and payments to flash sales, built on one running Mumbai example.26 min read · Updated 24 Oct 2026
• Design a Ride-Hailing App Like Uber: Matching and SurgeSystem design · A plain-English guide to designing a ride-hailing app like Uber or Ola: live driver locations, matching and surge pricing, built on one running example in Guwahati.25 min read · Updated 24 Oct 2026
• Design WhatsApp: Delivery Receipts, Groups and EncryptionSystem design · A plain-English guide to WhatsApp system design: open connections, offline inboxes, honest delivery ticks, group fan-out with sender keys and end-to-end encryption, shown on one running example of a family and small-business chat app.25 min read · Updated 24 Oct 2026
• Agent Skills Explained: Packaging Procedures in a SKILL.md FolderAI and GenAI · A plain-English guide to agent skills: the open SKILL.md folder format, how agents load a skill only when a task needs it, how skills differ from system prompts, tools and RAG, and how to review and test one, shown on one running example of a release-notes skill.22 min read · Updated 24 Oct 2026
• AWS US-EAST-1 Outage (October 2025) Explained: How a DNS Race Broke DynamoDBSystem design · A plain-English guide to the AWS us-east-1 outage of 19 and 20 October 2025: how a DNS automation race emptied DynamoDB's record and how EC2 and load balancers followed, shown on one running example of a bill-payments app.21 min read · Updated 24 Oct 2026
• October 2026 Brotli Vulnerability Explained: Find the Decoder Your App RunsBackend · A plain-English guide to the Brotli vulnerability CVE-2026-111497: which Python HTTP clients decode Brotli for you, how to find the copy your app loads and why version numbers mislead, shown on one running example of a Python service that fetches supplier feeds and receives webhooks.22 min read · Updated 24 Oct 2026
• Bun Check Explained: Type-Check TypeScript Before You Run, Test or BuildBackend · A plain-English guide to bun check, the TypeScript type checker built into Bun 1.4.3 and 1.4.4: how it compares with tsc, the --check flag, CI output and its limits, shown on one running example of an order-total bug.20 min read · Updated 24 Oct 2026
• Chrome's October 2026 Privacy Sandbox Removal Explained: What Ad Code Must DoFrontend · A plain-English guide to the Chrome Privacy Sandbox removal: which ad APIs go, the October and November 2026 dates, why stubs fool feature detection and how to fix ad code, shown on one running example of a news site's ad script.21 min read · Updated 24 Oct 2026
• Database Indexes Explained: B-Trees, Composite Keys and Write CostsBackend · A plain-English guide to database indexes: how a B-tree finds a row, how to order composite index columns, covering indexes, selectivity and what each index costs on writes, shown on one running example of an online shop's orders table.24 min read · Updated 24 Oct 2026
• DNS Compression Pointer Vulnerability Explained: Per-Name vs Per-Packet CapsBackend · A plain-English guide to the October 2026 DNS compression pointer vulnerability: how RFC 1035 pointers shrink names, why reading them can be made expensive and what Unbound, PowerDNS and dnspython now limit, shown on one running example of a startup's resolver and Python mail checker.20 min read · Updated 24 Oct 2026