⏱ 8 min read Bulk Data Import System Low-Level Design Bulk import is one of those features that looks straightforward until a user uploads […] Read article

⏱ 8 min read Data Retention Policy System Low-Level Design Every production database accumulates data that must eventually be purged, archived, or anonymized — Read article

⏱ 7 min read Push Notification System Low-Level Design A push notification system must reliably deliver time-sensitive messages to millions of devices across Android Read article

⏱ 7 min read Two-Factor Authentication Backup Codes: Low-Level Design When a user loses access to their TOTP authenticator app, backup codes are the Read article

⏱ 11 min read Overview A user segmentation system lets product and marketing teams define rule-based groups of users — “enterprise plan users who Read article

⏱ 9 min read Overview A content scheduler lets authors queue posts, stories, social updates, or any content entity for automatic publishing or unpublishing Read article

⏱ 11 min read Overview A file upload system must handle large binary transfers reliably — resuming interrupted uploads, scanning for malware, validating content Read article

⏱ 8 min read Overview A token bucket rate limiter controls how many requests a client can make within a time period while allowing Read article

⏱ 7 min read Overview A price history system records product price changes over time, enables historical chart queries, and fires alerts when a Read article

⏱ 9 min read Overview A digest email system aggregates user-relevant events over a configurable time window and delivers a single summarized email rather Read article

⏱ 9 min read Tenant Isolation System: Low-Level Design A multi-tenant SaaS application serves many organizations (tenants) from a shared infrastructure. Tenant isolation ensures Read article

⏱ 10 min read Multi-Region Failover System: Low-Level Design A multi-region failover system routes traffic away from a failing region to a healthy standby, Read article

⏱ 10 min read Distributed Tracing System: Low-Level Design A distributed tracing system records the journey of a request as it propagates through multiple Read article

⏱ 10 min read Saga Orchestration System: Low-Level Design A saga is a sequence of local transactions, each in a separate service, that together Read article

⏱ 9 min read Canary Deployment System: Low-Level Design A canary deployment system routes a small fraction of production traffic to a new version Read article