Getting started

Register services once. Resolve typed dependencies.

Injex uses regular Python type hints. Application classes do not need base classes, constructor decorators, or framework-specific dependency hooks.

Install

Use the PyPI package in any Python 3.10+ project.

Register

Describe the service graph at the composition root.

Validate

Catch missing dependencies before startup code constructs real services.

Install

pip install injex

Minimal example

from injex import Container

class Repository:
    def save(self, email: str) -> int:
        return 42

class RegisterUser:
    def __init__(self, repository: Repository):
        self.repository = repository

    def execute(self, email: str) -> int:
        return self.repository.save(email)

container = Container()
container.add_singleton(Repository)
container.add_transient(RegisterUser)
container.assert_valid()

use_case = container.resolve(RegisterUser)

Lifetimes

Method	Meaning	Common use
`add_singleton()`	One instance reused for the app lifetime.	Settings, clients, repositories.
`add_transient()`	New instance on each resolve.	Use cases and commands.
`add_scoped()`	One instance per scope.	Request, job, or message state.

Keep registration code close to application startup. Treat it as your composition root, not as business logic.