Maximum cookie size easy to reach about sessionhandlercookie HOT 2 OPEN

In addition to compression, the PHP code should check if the cookie size exceeds 4093 bytes and throw an error or call some host app defined handler.
Browsers will ignore the respective Set-Cookie header silently. Browsers limit between 4093 bytes and 4096 bytes per cookie (remember that some servers limit the entire header to small values like these).

from sessionhandlercookie.

brotli compresses better than gzip by about 22%.
This comes in handy for cookies :)

Not sure if included in public repos yet
https://github.com/kjdev/php-ext-brotli

But it would be much better than gzip, when/if compression support is added.

Edit: Now included in public repos.
https://centos.pkgs.org/7/remi-x86_64/php72-php-brotli-0.5.0-1.el7.remi.x86_64.rpm.html https://centos.pkgs.org/7/remi-x86_64/php70-php-brotli-0.5.0-1.el7.remi.x86_64.rpm.html
etc.

from sessionhandlercookie.