## Dependency Injection

Using `BackgroundTasks` also works with the dependency injection system, you can declare a parameter of type `BackgroundTasks` at multiple levels: in a *path operation function*, in a dependency (dependable), in a sub-dependency, etc.

**FastAPI** knows what to do in each case and how to re-use the same object, so that all the background tasks are merged together and are run in the background afterwards:

=== "Python 3.10+"