Tutorial: Enable gzip compression in nginx on a Plesk for more speed and smaller file size

1. Log in to Plesk.
2. Go to Domains > example.com > Hosting & DNS > Apache & nginx Settings.
3. Add the following directives to the Additional nginx directives field:

gzip on;
gzip_disable "MSIE [1-6]\\.(?!.*SV1)";
gzip_proxied any;
gzip_comp_level 5;
gzip_types text/plain text/css application/javascript application/x-javascript text/xml application/xml application/rss+xml text/javascript image/x-icon image/bmp image/svg+xml;
gzip_vary on;

https://support.plesk.com/hc/en-us/articles/12377854166935-How-to-enable-disable-gzip-compression-in-nginx-on-a-Plesk-server