What is Django REST Framework?

It supplies the layer between your models and JSON: serialisers that validate incoming data and shape outgoing data, view classes that map HTTP verbs onto the usual database operations, routers that generate the URLs, and permission classes that run before anything touches the database. It also renders a browsable version of the API, which is genuinely useful when a frontend developer is working against it.

The predictable failure is performance rather than correctness. Nested serialisers make it very easy to write an endpoint that issues a separate database query for every item in a list, which is fine on your development data and slow in production. The fix is explicit — telling the ORM upfront which related records to fetch — but nothing warns you, so it needs checking before launch rather than after a complaint.