What is the difference between a monorepo and a standard NestJS project structure?

0-2 years experience

1. 1If you need to add a new NestJS microservice that reuses a validation utility from an existing app, would you place it in the same repository or a separate one? Walk me through the folder layout you’d create.
2. 2You clone a NestJS project that follows the typical single‑repo layout and need to add a shared library for logging. What steps would you take, and what problems might you hit compared to using a monorepo?
3. 3When you run `npm run start` in a monorepo that contains two NestJS apps, how does the CLI know which app to launch, and how would you configure it?

2-5 years experience

1. 1Our monorepo has three NestJS services and a shared UI library. After a recent change in the shared library, one service started failing. How would you debug the issue, and what does the monorepo structure tell you about possible root causes?
2. 2You need to onboard a junior developer quickly. Would you choose a monorepo or a standard NestJS project layout for the first sprint? Explain the trade‑offs in onboarding speed, build times, and code discoverability.
3. 3During CI the build time for a NestJS app inside a monorepo doubled after adding another service. Which parts of the monorepo setup could cause this slowdown, and how would you address it?

5-8 years experience

1. 1Design a CI/CD pipeline for a monorepo that contains multiple NestJS microservices, each needing independent deployments. What challenges does the monorepo introduce, and how would you mitigate them?
2. 2Explain how you would version and publish shared modules in a monorepo versus a standard NestJS repo when different services require different versions of the same library.
3. 3If you must scale a NestJS application horizontally and you have the option of a monorepo or separate repos, how does the repository structure affect deployment strategies, runtime performance, and operational overhead?

8+ years experience

1. 1Our organization is planning to migrate from several independent NestJS repositories to a single monorepo. What long‑term architectural implications should we evaluate, including tooling, team autonomy, and dependency management?
2. 2Describe a phased strategy to move existing NestJS services into a monorepo without disrupting ongoing releases, and how you would measure the success of the migration.
3. 3In a large enterprise with dozens of NestJS services, how would you enforce consistent coding standards and coordinated updates of shared libraries across the monorepo, and what governance model would you propose?