Documentation

Typed dependency injection for small Python apps.

Injex wires services, CLIs, workers, and tests with regular Python type hints, explicit registrations, scoped lifetimes, overrides, and startup validation.

Python 3.10–3.13 Zero runtime dependencies PEP 561 typed

Start Getting started Install, register services, validate the graph, resolve use cases. Safety Graph validation Find missing registrations and cycles before services are built. Decision Comparison guide Choose between manual wiring, framework DI, Injex, and larger containers. Reference API reference Container methods, scopes, overrides, validation, and exceptions. Guide Python dependency injection Understand when DI helps in Python and how Injex stays small. Article Why tiny Python DI A shareable article about explicit wiring for Python services.

Install

pip install injex

Best fit

Service layers reused by API handlers, CLIs, workers, and tests.
Clean architecture code that should not depend on a web framework.
Tests that need temporary dependency overrides.
Startup checks that should validate the dependency graph early.

Rule of thumb: keep container calls at the composition root. Application services should depend on normal Python types.