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BlackSheep implements built-in features to handle automatic response compression. This page describes:

  • How to use the GzipMiddleware to enable gzip compression


To enable automatic compression of response bodies using gzip, use the GzipMiddleware like in the following example:

from blacksheep import Application
from blacksheep.server.compression import GzipMiddleware

app = Application()


Or, in alternative:

from blacksheep import Application
from blacksheep.server.compression import use_gzip_compression

app = Application()


Not for streamed content

The GzipMiddleware does not compress bytes streamed using the StreamedContent class (used by default when serving files), it only compresses whole bodies like, for example, those that are generated when returning JSON content to the client.


The following table describes options for the GzipMiddleware constructor.

Option Type Description
min_size int (default 500) The minimum size before applying compression to response bodies.
comp_level int (default 5) The compression level, as passed to gzip.compress function.
handled_types Optional[Iterable[bytes]] Control which content types can be compressed by the specific instance of GzipMiddleware.
executor Optional[Executor] (default None) Control which instance of concurrent.future.Executor is used to compress - if not specified the default executor handled by run_in_executor is used.

When handled_types is not specified for an instance of GzipMiddleware, compression is applied by default to content types containing any of the following strings:

  • json
  • xml
  • yaml
  • html
  • text/plain
  • application/javascript
  • text/css
  • text/csv

Last modified on: 2023-12-18 17:52:09