Django REST Framework vs FastAPI: Which for a New API?

How Django REST Framework and FastAPI actually differ for building an API, and which one fits a new project vs an existing Django codebase

Both solve the same core problem — building a JSON API in Python — but they start from opposite ends: DRF extends an existing full-stack framework, FastAPI is API-only from the ground up.

The core difference

Django REST Framework is a layer on top of Django — you get Django’s ORM, admin panel, and authentication system, with DRF adding serializers and viewsets for the API surface specifically. FastAPI has no opinion on your database layer or admin tooling; it’s built around request validation via Pydantic type hints and native async support, with automatic OpenAPI documentation generated directly from your function signatures.

Async support

FastAPI is async-first throughout — every route can be async def with no extra configuration. Django gained async views more recently, and DRF’s own internals aren’t fully async-native, so a DRF project mixing sync and async code needs more care than a FastAPI project where async is the default assumption from the start.

Automatic documentation

FastAPI generates interactive OpenAPI/Swagger documentation automatically from type hints — always in sync with the actual code, no separate step. DRF’s browsable API serves a similar purpose (letting you inspect and test endpoints in a browser) but is a different mechanism — an HTML interface generated per-view rather than a formal OpenAPI spec, though DRF can generate OpenAPI schemas with additional tooling if needed.

The database and admin question

This is usually the deciding factor. If you want Django’s ORM, migrations, and built-in admin panel for managing data alongside your API, DRF gives you all of that in one project. FastAPI has no built-in ORM or admin — you’d pair it with something like SQLAlchemy and build any admin tooling yourself, or add a separate package for it. Wanting Django’s ecosystem is a real, legitimate reason to choose DRF even for an API-only project.

Which one for a new project

• Starting fresh, API-only, no need for Django’s admin/ORM → FastAPI
• Already on Django, or want the admin panel and ORM alongside the API → DRF
• High-concurrency async workload is a known requirement from day one → FastAPI, though Django’s async views have narrowed this gap

Neither is a wrong choice for a well-scoped project — the decision is really about whether Django’s broader ecosystem is something you want, not which framework is objectively better at serving JSON.