The ngx_http_gzip_static_module module allows to send precompressed files with the “.gz” filename extension instead of regular files.

This module is not built by default, it should be enabled with the --with-http_gzip_static_module configuration parameter.

gzip_static  on;
gzip_proxied expired no-cache no-store private auth;

gzip_static off;

Enables or disables checking the existence of precompressed files. The following directives are also taken into account: gzip_http_version, gzip_proxied, gzip_disable, and gzip_vary.

The files can be compressed using the gzip command, or any other compatible. It is recommended that the modification date and time of original and compressed files be the same.