modern-di 4.2.1

Project	Badges
modern-di
modern-di-aiogram
modern-di-aiohttp
modern-di-arq
modern-di-celery
modern-di-fastapi
modern-di-fastmcp
modern-di-faststream
modern-di-flask
modern-di-grpc
modern-di-litestar
modern-di-pytest
modern-di-starlette
modern-di-taskiq
modern-di-typer

modern-di is a dependency injection container for Python 3.11+. You declare how each object is built, and the container builds it, fills its constructor from type annotations, keeps it for as long as its scope lives, and runs its teardown when that scope closes.

• Constructor parameters are matched by type, and you can pass explicit arguments where a type is ambiguous.
• Scopes (APP, REQUEST and finer ones) decide how long a cached object lives, and finalizers close it when its scope ends.
• container.validate() finds cycles and scope errors at startup instead of on the first request.
• One override replaces a dependency for the whole container tree, so HTTP handlers, workers and direct unit tests all see the same fake.
• Typed end to end, with no type-checker plugin.
• Integrations for aiogram, aiohttp, arq, Celery, FastAPI, FastMCP, FastStream, Flask, gRPC, Litestar, Starlette, taskiq and Typer, plus modern-di-pytest, which turns dependencies into pytest fixtures.

Install

uv add modern-di      # or: pip install modern-di

Quick start

import dataclasses
from modern_di import Container, Group, Scope, providers


@dataclasses.dataclass(kw_only=True, slots=True, frozen=True)
class Settings:
    database_url: str = "postgresql+asyncpg://localhost/app"


@dataclasses.dataclass(kw_only=True, slots=True)
class UserRepository:
    settings: Settings  # auto-injected by type


class Dependencies(Group):
    settings = providers.Factory(Settings, scope=Scope.APP)
    user_repository = providers.Factory(UserRepository, scope=Scope.REQUEST)


with Container(groups=[Dependencies]) as container:
    with container.build_child_container(scope=Scope.REQUEST) as request:
        repo = request.resolve(UserRepository)
        print(repo.settings.database_url)

See the documentation for scopes, lifecycles, finalizers, and framework integrations. modern-di is deliberately conservative; see Design decisions for what it leaves out on purpose, including auto-binding, in-package integrations, and graph rendering.

Usage examples:

• with Litestar: litestar-sqlalchemy-template
• with FastAPI: fastapi-sqlalchemy-template

Links

• Documentation
• PyPI
• License

Part of modern-python

Browse the full list of templates and libraries in modern-python. See the org profile for the categorized index.