'mod_pagespeed' is module of Apache which is nothing but plugin which is used for compressing the external code of JavaScript and CSS. It also used to increase the page load time as it combines multiple external JavaScript file in one file so it reduces the http request.
Steps to install the mod_pagespeed on EasyApache 4-
1. SSH to server with root access and fire below commands
$> yum install rpm-build cpio ea-apache24-mod_version
$> wget https://github.com/Prajithp/cpanel/raw/master/EA4/ea-apache24-mod_pagespeed-1.9-32.11.src.rpm
$> rpmbuild --rebuild ea-apache24-mod_pagespeed-1.9-32.11.src.rpm
$> rpm -ivh /root/rpmbuild/RPMS/x86_64/ea-apache24-mod_pagespeed-1.9-32.11.x86_64.rpm
$> yum install rpm-build cpio ea-apache24-mod_version
$> wget https://github.com/Prajithp/cpanel/raw/master/EA4/ea-apache24-mod_pagespeed-1.9-32.11.src.rpm
$> rpmbuild --rebuild ea-apache24-mod_pagespeed-1.9-32.11.src.rpm
$> rpm -ivh /root/rpmbuild/RPMS/x86_64/ea-apache24-mod_pagespeed-1.9-32.11.x86_64.rpm
2. After that restart Apache service using below command -
$>/etc/init.d/httpd restart
3. Now you will need to clone the script in your cPanel server by below command -
/usr/local/cpanel/3rdparty/bin/git clone https://github.com/pagespeed/cpanel.git /tmp/pagespeed/
/usr/local/cpanel/3rdparty/bin/git clone https://github.com/pagespeed/cpanel.git /tmp/pagespeed/
4. Now create Speed.pm.tar.gz -
$> cd /tmp/pagespeed/Easy
$> tar -zcvf Speed.pm.tar.gz pagespeed
$> mkdir -p /var/cpanel/easy/apache/custom_opt_mods/Cpanel/Easy
$> mv Speed.pm Speed.pm.tar.gz -t /var/cpanel/easy/apache/custom_opt_mods/Cpanel/Easy/
$> cd && rm -rf /tmp/pagespeed
$> cd /tmp/pagespeed/Easy
$> tar -zcvf Speed.pm.tar.gz pagespeed
$> mkdir -p /var/cpanel/easy/apache/custom_opt_mods/Cpanel/Easy
$> mv Speed.pm Speed.pm.tar.gz -t /var/cpanel/easy/apache/custom_opt_mods/Cpanel/Easy/
$> cd && rm -rf /tmp/pagespeed
5. For verifying it you can login to WHM >> EasyApache >> Search for mod_pagespeed option.
All done! 
