There are two ways to generate an OpenAPI spec in Django Rest Framework: CLI command and API endpoint.

How it works

The actual spec is produced by an underlying generator class, called by either a CLI command or an API endpoint. Long story short: generator collects the project endpoints from settings.ROOT_URLCONF and compiles a spec for each of them. To be able to generate a spec you need to install a pyyaml package first:

pip install pyyaml

CLI command

To generate a spec via CLI command, call a generateschema management command:

python manage.py generateschema

This command outputs an OpenAPI spec in YAML format by default.

API endpoint

To generate a spec via API endpoint, add this code to urls.py:

from django.urls import path
from rest_framework.schemas import get_schema_view

urlpatterns = [
    path('schema/', get_schema_view())
    ...
]

Now, when you call GET /schema/, DRF will respond with an OpenAPI spec.