Frontend System Design

A frontend system is a set of numbers (rows, users, bytes, updates per second, milliseconds) and the simplest design that meets them, revised each time a number grows past what the design can carry. Every revision is a named trade-off, and the skill is knowing which number breaks which design, and what to reach for next.

Nine systems, each run the same way the Core Banking module ran its rounds: a product brief, the questions that pin it down, requirements with numbers, the naive version, the failure demonstrated, the better version, and the point at which that one fails too. A data table that grows to ten million rows, a compute job that must not freeze the tab, a media pipeline, a dashboard at sixty frames, a collaborative editor, a list of a million items, a social feed, a real-time layer, and a trading screen with a latency budget.