KPHP is a PHP compiler. It compiles a limited subset of PHP to a native binary running faster than PHP. KPHP was developed at VK.com and maintained as proprietary for years — until open-sourced in late 2020. "I tried to compile PHP code, but failed". This situation is quite common. KPHP rarely compiles already existing code without errors. It usually takes some time to rewrite PHP code for it to be compilable with KPHP. Read more about this in compiling an existing project.