django-storages-s3

Install django-storages[s3] and boto3, add "storages" to INSTALLED_APPS, then define the STORAGES dict with S3Boto3Storage as the default backend. Load credentials from environment variables or an IAM role, and set separate location prefixes for media and static files.

Set querystring_auth=True and custom_domain=None on the private backend, then calling .url on a file field returns a presigned GET URL automatically. For direct browser uploads, use boto3's generate_presigned_post to let clients upload straight to S3.

Yes, the STORAGES dict introduced in Django 4.2 works unchanged through Django 5.2 LTS and 6.0. The legacy DEFAULT_FILE_STORAGE and STATICFILES_STORAGE settings were removed in Django 5.1 and are silently ignored there.

Buckets created after April 2023 have ACLs disabled by default, so any default_acl value other than None raises this error. Set default_acl=None and control public access through a bucket policy instead of per-object ACLs.

Use override_settings to swap the STORAGES default backend to InMemoryStorage so tests never touch AWS. When code calls boto3 directly, such as for presigned URLs, mock the S3 API with the moto library instead.

Common causes are setting custom_domain alongside querystring_auth, server clock skew, signing for the wrong region, or caching a presigned URL past its AWS_QUERYSTRING_EXPIRE lifetime. Set custom_domain=None and generate URLs per request.