The 80/20 Library-First Monorepo: Why Your Apps Should Be Almost Empty

Most monorepos pay lip service to "share code via libraries." In practice, apps grow huge and libraries stay shallow. The shared/ folder becomes a junk drawer. New code goes wherever's easiest, which is usually wherever the developer is already typing - the app. After scaling our frontend monorepo to 19 applications and 86 libraries (roughly 74,000 lines of TypeScript), I've seen this pattern from both sides: as the architect setting it up, and as the engineer who later inherits it. The takeaway