Real-Time Scoring Pipeline Every transaction enters the fraud scoring pipeline synchronously before a payment decision is returned. The flow: transaction […]

Cart Storage Options There are three main approaches to storing a shopping cart. Client-side storage keeps the cart in the

Config Data Model A configuration management system stores each configuration entry as a structured record with the following fields: key

Home Hub Architecture The home hub is the central controller for all smart home devices in a physical residence. Deployed

Driver State Machine Every driver in the system exists in one of four states: offline, available, on_trip, or returning. The

Poll and voting systems appear in everything from social media reactions to high-stakes organizational decisions. The engineering challenges span idempotent

Calendar and scheduling systems look deceptively simple on the surface but contain significant engineering depth. Recurring events, timezone transitions, multi-user

Ticket booking systems handle some of the most demanding concurrency scenarios in software engineering. When a popular concert goes on

State Machine The circuit breaker is a three-state machine wrapped around each outbound call to a downstream dependency. In the

Training Job Orchestration A training job submission API accepts the full specification of a run: the training script path, the

A database connection pool is one of the most impactful infrastructure components in any application that talks to a relational

Search autocomplete is a latency-critical, high-read-volume system that combines data structures, probabilistic algorithms, and multi-layer caching to return relevant suggestions

Designing a media encoding pipeline requires coordinating upload handling, distributed transcoding, codec decisions, and delivery optimization into a coherent system.

PKI Hierarchy A certificate authority system is built on a chain of trust. The root CA is the ultimate trust