php-fpm is a "PHP FastCGI Process Manager", i.e. a program that waits for a web server to start a php script via the CGI interface. php-fpm forwards this request to an existing php process (which is also called php-fpm) or starts a new one if necessary.

The configuration settings for this can be found in /usr/local/etc/php-fpm.conf, which also includes all .conf files under /usr/local/etc/php-fpm.d. The main configuration file contains parameters that usually do not need to be touched. The file www.conf is pre-installed in php-fpm.d as an additional configuration file. For both files there is also a sample file with the extension .conf.default, these files have no technical function.