Standard mode is a single application in one repo with one src/ folder and one build output. Monorepo mode hosts multiple applications and shared libraries under one repo managed by the NestJS CLI. Libraries are shared code compiled once and imported by apps via path aliases rather than npm packages.
Standard — one app, one tsconfig, one build. Best for standalone APIs or microservices deployed independently.
Monorepo — multiple apps sharing libraries under one repo. Best when apps share significant code.
Libraries use @app/common path aliases instead of npm package names — cross-project changes are instant.
The NestJS CLI manages monorepo builds with nest build api or nest build admin per app.
Choose monorepo when you have multiple NestJS apps that share DTOs, utilities, or config logic.