Amazon S3


There are two backends for interacting with Amazon’s S3, one based on boto3 and an older one based on boto. It is highly recommended that all new projects (at least) use the boto3 backend since it has many bug fixes and performance improvements over boto and is the future; boto is lightly maintained if at all. The boto3 based backend will continue to be maintained for the foreseeable future.

For historical completeness an extreme legacy backend was removed in version 1.2

If using the boto backend on a new project (not recommended) it is recommended that you configure it to also use AWS Signature Version 4. This can be done by adding S3_USE_SIGV4 = True to your settings and setting the AWS_S3_HOST configuration option. For regions created after January 2014 this is your only option if you insist on using the boto backend.


To use boto3 set:

DEFAULT_FILE_STORAGE = 'storages.backends.s3boto3.S3Boto3Storage'

To use the boto version of the backend set:

DEFAULT_FILE_STORAGE = 'storages.backends.s3boto.S3BotoStorage'

To allow collectstatic to automatically put your static files in your bucket set the following in your

STATICFILES_STORAGE = 'storages.backends.s3boto3.S3Boto3Storage'
Your Amazon Web Services access key, as a string.
Your Amazon Web Services secret access key, as a string.
Your Amazon Web Services storage bucket name, as a string.
AWS_DEFAULT_ACL (optional, None or canned ACL, default public-read)
Must be either None or from the list of canned ACLs. If set to None then all files will inherit the bucket’s ACL.


The default value of public-read is insecure and will be changing to None in a future release of django-storages. Please set this explicitly to public-read if that is the desired behavior.

AWS_BUCKET_ACL (optional, default public-read)

Only used if AWS_AUTO_CREATE_BUCKET=True. The ACL of the created bucket.

Must be either None or from the list of canned ACLs. If set to None then the bucket will use the AWS account’s default.


The default value of public-read is insecure and will be changing to None in a future release of django-storages. Please set this explicitly to public-read if that is the desired behavior.

If set to True the bucket specified in AWS_STORAGE_BUCKET_NAME is automatically created.
AWS_HEADERS (optional - boto only, for boto3 see AWS_S3_OBJECT_PARAMETERS)

If you’d like to set headers sent with each file of the storage:

    'Expires': 'Thu, 15 Apr 2010 20:00:00 GMT',
    'Cache-Control': 'max-age=86400',
AWS_S3_OBJECT_PARAMETERS (optional - boto3 only)

Use this to set object parameters on your object (such as CacheControl):

    'CacheControl': 'max-age=86400',
AWS_QUERYSTRING_AUTH (optional; default is True)
Setting AWS_QUERYSTRING_AUTH to False to remove query parameter authentication from generated URLs. This can be useful if your S3 buckets are public.
AWS_S3_MAX_MEMORY_SIZE (optional; default is 0 - do not roll over)
The maximum amount of memory a file can take up before being rolled over into a temporary file on disk.
AWS_QUERYSTRING_EXPIRE (optional; default is 3600 seconds)
The number of seconds that a generated URL is valid for.
AWS_S3_ENCRYPTION (optional; default is False)
Enable server-side file encryption while at rest.
AWS_S3_FILE_OVERWRITE (optional: default is True)
By default files with the same name will overwrite each other. Set this to False to have extra characters appended.

AWS_S3_HOST (optional - boto only, default is

To ensure you use AWS Signature Version 4 it is recommended to set this to the host of your bucket. See the S3 region list to figure out the appropriate endpoint for your bucket. Also be sure to add S3_USE_SIGV4 = True to


The signature versions are not backwards compatible so be careful about url endpoints if making this change for legacy projects.

AWS_LOCATION (optional: default is ‘’)
A path prefix that will be prepended to all uploads
AWS_IS_GZIPPED (optional: default is False)
Whether or not to enable gzipping of content types specified by GZIP_CONTENT_TYPES
GZIP_CONTENT_TYPES (optional: default is text/css, text/javascript, application/javascript, application/x-javascript, image/svg+xml)
When AWS_IS_GZIPPED is set to True the content types which will be gzipped
AWS_S3_REGION_NAME (optional: default is None)
Name of the AWS S3 region to use (eg. eu-west-1)
AWS_S3_USE_SSL (optional: default is True)
Whether or not to use SSL when connecting to S3.
AWS_S3_VERIFY (optional: default is None - boto3 only)
Whether or not to verify the connection to S3. Can be set to False to not verify certificates or a path to a CA cert bundle.
AWS_S3_ENDPOINT_URL (optional: default is None, boto3 only)
Custom S3 URL to use when connecting to S3, including scheme. Overrides AWS_S3_REGION_NAME and AWS_S3_USE_SSL.
AWS_S3_ADDRESSING_STYLE (default is None, boto3 only)
Possible values virtual and path.
AWS_S3_PROXIES (boto3 only, default None)
A dictionary of proxy servers to use by protocol or endpoint, e.g.: {‘http’: ‘’, ‘http://hostname’: ‘’}.


The minimum required version of boto3 to use this feature is 1.4.4

AWS_S3_CALLING_FORMAT (optional: default is SubdomainCallingFormat())
Defines the S3 calling format to use to connect to the static bucket.

AWS_S3_SIGNATURE_VERSION (optional - boto3 only)

As of boto3 version 1.4.4 the default signature version is s3v4.

Set this to use an alternate version such as s3. Note that only certain regions support the legacy s3 (also known as v2) version. You can check to see if your region is one of them in the S3 region list.


The signature versions are not backwards compatible so be careful about url endpoints if making this change for legacy projects.

Migrating from Boto to Boto3

Migration from the boto-based to boto3-based backend should be straightforward and painless.

The following adjustments to settings are required:

  • Rename AWS_HEADERS to AWS_S3_OBJECT_PARAMETERS and change the format of the key names as in the following example: cache-control becomes CacheControl.
  • If AWS_S3_CALLING_FORMAT is set to VHostCallingFormat set AWS_S3_ADDRESSING_STYLE to virtual
  • Replace AWS_S3_HOST and AWS_S3_PORT with AWS_S3_ENDPOINT_URL (this is not necessary if AWS_S3_HOST is only set in order to handle signature versions)
  • If using signature version s3v4 you can remove S3_USE_SIGV4
  • If you persist urls and rely on the output to use the signature version of s3 set AWS_S3_SIGNATURE_VERSION to s3
  • Update DEFAULT_FILE_STORAGE and/or STATICFILES_STORAGE to storages.backends.boto3.S3Boto3Storage

Additionally you must install boto3 (boto is no longer required). In order to use all currently supported features 1.4.4 is the minimum required version although we always recommend the most recent.

Please open an issue on the GitHub repo if any further issues are encountered or steps were omitted.


If you’re using S3 as a CDN (via CloudFront), you’ll probably want this storage to serve those files using that:



Django’s STATIC_URL must end in a slash and the AWS_S3_CUSTOM_DOMAIN must not. It is best to set this variable indepedently of STATIC_URL.

Keep in mind you’ll have to configure CloudFront to use the proper bucket as an origin manually for this to work.

If you need to use multiple storages that are served via CloudFront, pass the custom_domain parameter to their constructors.


Standard file access options are available, and work as expected:

>>> from import default_storage
>>> default_storage.exists('storage_test')
>>> file ='storage_test', 'w')
>>> file.write('storage contents')
>>> file.close()

>>> default_storage.exists('storage_test')
>>> file ='storage_test', 'r')
'storage contents'
>>> file.close()

>>> default_storage.delete('storage_test')
>>> default_storage.exists('storage_test')


An object without a file has limited functionality:

>>> obj1 = MyStorage()
>>> obj1.normal
<FieldFile: None>
>>> obj1.normal.size
Traceback (most recent call last):
ValueError: The 'normal' attribute has no file associated with it.

Saving a file enables full functionality:

>>>'django_test.txt', ContentFile('content'))
>>> obj1.normal
<FieldFile: tests/django_test.txt>
>>> obj1.normal.size

Files can be read in a little at a time, if necessary:

>>> '-'.join(obj1.normal.chunks(chunk_size=2))

Save another file with the same name:

>>> obj2 = MyStorage()
>>>'django_test.txt', ContentFile('more content'))
>>> obj2.normal
<FieldFile: tests/django_test_.txt>
>>> obj2.normal.size

Push the objects into the cache to make sure they pickle properly:

>>> cache.set('obj1', obj1)
>>> cache.set('obj2', obj2)
>>> cache.get('obj2').normal
<FieldFile: tests/django_test_.txt>

Deleting an object deletes the file it uses, if there are no other objects still using that file:

>>> obj2.delete()
>>>'django_test.txt', ContentFile('more content'))
>>> obj2.normal
<FieldFile: tests/django_test_.txt>

Default values allow an object to access a single file:

>>> obj3 = MyStorage.objects.create()
>>> obj3.default
<FieldFile: tests/default.txt>
'default content'

Clean up the temporary files:

>>> obj1.normal.delete()
>>> obj2.normal.delete()
>>> obj3.default.delete()
>>> obj4.random.delete()