Django Ninja is a Python library that provides a FastAPI-inspired, type-hint-driven framework for building REST APIs on top of Django. It leverages Pydantic v2 for request validation and serialization, and automatically generates OpenAPI 3.0 schemas with interactive Swagger UI and Redoc documentation. The library offers a decorator-based API definition (e.g., @api.get, @router.post), supports sync and async views, and includes built-in support for authentication (API keys, HTTP Basic/Bearer, Django session), throttling, pagination (limit-offset, page-number, cursor), filtering (declarative FilterSchema), file uploads, streaming responses (SSE, JSONL), and CSRF protection. It integrates deeply with Django's ORM through ModelSchema and create_schema, and provides a TestClient for fast, serverless testing. The architecture is modular: NinjaAPI is the central application class, Router groups endpoints with nested routing and auth inheritance, and Operation handles the request lifecycle (auth, throttle, validation, response). The codebase is well-structured, extensively tested (100% coverage target), and actively maintained with broad compatibility across Python 3.7–3.14 and Django 3.1–6.1. It is a mature, production-ready framework used by multiple companies.