⏱ 7 min read Referral Program System: Low-Level Design A referral program drives user acquisition by rewarding existing users who bring in new ones. […] Read article

⏱ 8 min read Media Processing Pipeline: Low-Level Design A media processing pipeline handles the journey from raw video upload to CDN-delivered adaptive bitrate Read article

⏱ 10 min read Incident Management System: Low-Level Design An incident management system ingests alerts from monitoring infrastructure, classifies them by severity, pages the Read article

⏱ 9 min read Data Synchronization System: Low-Level Design A data synchronization system allows multiple devices or replicas to independently modify shared data and Read article

⏱ 9 min read Content Recommendation System: Low-Level Design A content recommendation system must serve personalized item lists at low latency while continuously incorporating Read article

⏱ 9 min read Permission Delegation System: Low-Level Design Permission delegation allows a user (delegator) to grant a subset of their own permissions to Read article

⏱ 8 min read Notification Routing Engine: Low-Level Design A notification routing engine sits between the event source and the delivery channels (email, SMS, Read article

⏱ 8 min read Log Aggregation Pipeline: Low-Level Design A log aggregation pipeline collects structured logs from thousands of services, parses and enriches them, Read article

⏱ 8 min read Live Chat System: Low-Level Design A live chat system must maintain persistent WebSocket connections, fan out messages in milliseconds to Read article

⏱ 8 min read Threaded Comment System: Low-Level Design Threaded comment systems power discussion on news sites, forums, Reddit-style boards, and product pages. The Read article

⏱ 8 min read Knowledge Base System Low-Level Design A knowledge base must do three things well: let authors maintain accurate articles without losing Read article

⏱ 8 min read Image Moderation Pipeline Low-Level Design User-generated image content requires automated screening at scale. A purely manual review operation collapses under Read article

⏱ 8 min read Tax Calculation Engine Low-Level Design Tax calculation sits at the intersection of accuracy and auditability: a one-cent rounding error multiplied Read article

⏱ 8 min read Device Management System Low-Level Design A device management system answers three security questions: what devices have accessed an account, how Read article

⏱ 8 min read Audit Log Export System Low-Level Design Compliance teams and security analysts regularly need bulk exports of audit log data for Read article