Extra modules

Not everything can be @injectable. Config values, SDK clients from third-party libraries, environment-specific bindings — those live in extra_modules.

injector backend

Any callable that accepts an injector.Binder, or an injector.Module subclass.

# myapp/app_modules.py
import injector
from django.conf import settings
from stripe import StripeClient
from myapp.ports import IPaymentGateway, IDatabase

class AppModule(injector.Module):
    def configure(self, binder: injector.Binder) -> None:
        # Concrete SDK client
        binder.bind(
            StripeClient,
            to=StripeClient(api_key=settings.STRIPE_API_KEY),
            scope=injector.singleton,
        )
        # Config value
        binder.bind(str, to=settings.SECRET_KEY, scope=injector.singleton)

Register it:

class MyAppConfig(AutowiredAppConfig):
    name = "myapp"
    autowired_packages = ["myapp.services", "myapp.adapters"]
    autowired_extra_modules = [AppModule()]

Environment-specific bindings

The recommended pattern is one concrete @injectable per interface, with extra_modules swapping implementations in non-prod environments:

# myapp/apps.py
import os
from myapp.adapters.fakes import InMemoryPaymentGateway

extra = []
if os.environ.get("USE_FAKES"):
    def _fakes_module(binder):
        binder.bind(IPaymentGateway, to=InMemoryPaymentGateway)
    extra = [_fakes_module]

class MyAppConfig(AutowiredAppConfig):
    name = "myapp"
    autowired_packages = ["myapp"]
    autowired_extra_modules = extra

This keeps the code one concrete per interface while still giving you per-environment control.