What is the difference between a shared module and a global module in NestJS?

Difficulty: 4/10

module scope, dependency injection, global providers

A shared module exports providers so other modules can import it explicitly. A global module (decorated with @Global()) registers its exported providers application-wide so no explicit import is needed. Global modules should be registered only once in the root module and used sparingly to avoid hidden coupling.

A shared module is the standard pattern — it exports providers and must be imported explicitly by any module that wants to use them. A global module uses @Global() so its exports are available everywhere without needing to be imported.

Global module example

When to use each:

1
Shared module — default choice; explicit imports keep dependencies traceable.
2
Global module — use only for truly cross-cutting infrastructure like logging, config, or database connections.
3
Global modules should be registered only once, in the root AppModule.
4
Overusing @Global() leads to hidden coupling and makes modules harder to test in isolation.

Scenario Questions

0-2 years experience

Follow-up Questions