Popular System-Design Articles

A system design interview evaluates how an engineer turns an ambiguous product problem into a practical architecture. The goal is rarely to discover one perfect design. Interviewers are more interested in how requirements are clarified, assumptions are made, scale is estimated, components are select

A notification system delivers messages to users through channels such as mobile push, email, and SMS. Sending one notification is straightforward. Sending millions reliably becomes a distributed-systems problem involving asynchronous processing, fan-out, user preferences, provider rate limits, retr

System design decisions depend heavily on scale. An architecture serving 100 requests per second can look very different from one handling 100,000 requests per second, billions of stored objects, or millions of persistent connections.