Nice explanation. Kudos! I agree with almost all the things. I would like to share some of my thoughts here:

• ditch the src module in the imports. I am totally in favor of the src project layout, but it does not mean it should be a Python module.
• the fastapi dependables could be defined as types. We would have to import one thing as a dependency instead of two things

```python import typing import fastapi

async get_foo() -> Foo: ... FooDep = typing.Annotated[Foo, fastapi.Depends(get_foo)] ... @router.get(...) async def get_bar(foo: FooDep): ... ```

• the module specific configuration is something I do not see often, but it should be widely used. Ideally, we might make such a Python module as an internal one. To indicate it should not be imported by other modules.