What is HHVM (HipHop Virtual Machine)?
HHVM uses a just-in-time (JIT) compilation approach to achieve superior performance while maintaining the flexibility that PHP developers are accustomed to. To date, HHVM (and its predecessor HPHPc before it) has realized over a 9x increase in web request throughput and over a 5x reduction in memory consumption for Facebook compared with the PHP 5.2 engine + APC.
HHVM (HipHop Virtual Machine) is a tool in the Virtual Machine category of a tech stack.
Why developers like HHVM (HipHop Virtual Machine)
Drop-in PHP replacement
Works well with nginx
Backed by Facebook
Statically checked, typed language