⏱ 7 min read Database Sharding — Low-Level Design Database sharding horizontally partitions data across multiple database instances, each holding a subset of the […] Read article

⏱ 6 min read Read Replica Routing — Low-Level Design Read replica routing directs read queries to replica databases and write queries to the Read article

⏱ 6 min read Outbox Pattern — Low-Level Design The Transactional Outbox pattern ensures that database writes and message/event publishing happen atomically, without two-phase Read article

⏱ 7 min read Cursor Pagination — Low-Level Design Cursor pagination (also called keyset pagination) navigates large datasets stably and efficiently by using a Read article

⏱ 6 min read OAuth Social Login System — Low-Level Design An OAuth social login system allows users to authenticate via a third-party provider Read article

⏱ 6 min read Faceted Search System — Low-Level Design A faceted search system lets users narrow results through multiple filter dimensions simultaneously — Read article

⏱ 6 min read Soft Delete Pattern — Low-Level Design The soft delete pattern marks records as deleted without removing them from the database, Read article

⏱ 6 min read Password Reset Flow — Low-Level Design A password reset flow lets users regain account access via a verified email link. Read article

⏱ 6 min read Shopping Cart Persistence — Low-Level Design A shopping cart persistence system stores cart state across sessions and devices, merges guest Read article

⏱ 7 min read File Version Control System — Low-Level Design A file version control system tracks the history of changes to files, supports Read article

⏱ 6 min read User Blocking System — Low-Level Design A user blocking system prevents one user from seeing or interacting with another. It Read article

⏱ 7 min read Time Series Metrics System — Low-Level Design A time series metrics system stores and queries measurements that change over time: Read article

⏱ 6 min read Presence System — Low-Level Design A presence system tracks whether users are online, idle, or offline, and broadcasts status changes Read article

⏱ 7 min read Mentions and Notifications System — Low-Level Design A mentions system parses @username references in user content, identifies the mentioned users, Read article

⏱ 6 min read Live Comments System — Low-Level Design A live comments system streams new comments to all viewers of a piece of Read article