System Design

⏱ 6 min read An OCR service must handle raw document images, extract structured text, assess confidence, and process jobs asynchronously at scale. Here […] Read article

⏱ 5 min read Autocorrect differs from a spell checker in intent: rather than flagging errors for the user to fix, it silently replaces Read article

⏱ 7 min read API key rotation is a security control that limits the blast radius of a leaked credential. A well-designed rotation service Read article

⏱ 8 min read Configuration drift is one of the most common root causes of production incidents. A config diff and change management service Read article

⏱ 8 min read In a SaaS product, onboarding a new customer involves far more than creating a database row. The tenant provisioning service Read article

⏱ 7 min read Experiment Logging and Analysis Service An experiment logging and analysis service captures assignment and metric events from running A/B tests, Read article

⏱ 7 min read Real-Time Location Service A real-time location service ingests high-frequency position updates from mobile clients, indexes them for low-latency spatial queries, Read article

⏱ 6 min read Low Level Design: Pastebin Service A Pastebin service lets users store and share text (code, configs, logs) via a short Read article

⏱ 5 min read Upload Flow When a client uploads an image, the request hits an API gateway that performs initial validation: file size Read article

⏱ 4 min read Ingestion: Chunked Upload and Raw Storage Large video files cannot be uploaded in a single HTTP request reliably. The ingestion Read article

⏱ 5 min read A metrics collection service captures numeric measurements over time, stores them efficiently, and powers alerting and dashboards. This post covers Read article

⏱ 4 min read Streaming Analytics Service: Low Level Design A streaming analytics service ingests high-velocity event data, applies stateful computations in real time, Read article

⏱ 6 min read What Are Read Receipts? Read receipts tell message senders whether their messages have been delivered and read. The feature is Read article

⏱ 5 min read A news feed service delivers a ranked, personalized stream of posts to each user. The central design question is delivery Read article

⏱ 6 min read A payment dispute resolution service manages the lifecycle from the moment a customer contests a charge through investigation, bank communication, Read article