inversipy

A powerful and type-safe dependency injection/IoC (Inversion of Control) library for Python 3.12+.

Why inversipy?

• Zero runtime dependencies - Pure Python, nothing to install beyond the library itself
• Type annotation-based - Dependencies resolved using Python type hints
• Pure classes - No container coupling; classes remain framework-agnostic
• Async-first - First-class support for async dependencies and factories
• Validated - Catch configuration errors at startup, not at runtime

Key Features

• Container with registration, resolution, and composition
• Three scopes: Singleton, Transient, and Request
• Module system with public/private access control
• Property injection via Injectable base class
• Named dependencies for multiple implementations
• Collection injection with InjectAll
• Factory & Lazy injection for deferred resolution
• Optional dependencies with T | None
• Container freezing for runtime safety
• FastAPI integration
• Full MyPy support with strict typing

Quick Example

from inversipy import Container, Scopes

class Database:
    def query(self, sql: str) -> list:
        return ["result"]

class UserRepository:
    def __init__(self, db: Database) -> None:
        self.db = db

    def get_users(self) -> list:
        return self.db.query("SELECT * FROM users")

class UserService:
    def __init__(self, repo: UserRepository) -> None:
        self.repo = repo

    def list_users(self) -> list:
        return self.repo.get_users()

# Create container and register dependencies
container = Container()
container.register(Database, scope=Scopes.SINGLETON)
container.register(UserRepository)
container.register(UserService)

# Validate and freeze
container.validate()
container.freeze()

# Resolve dependencies
service = container.get(UserService)
users = service.list_users()