Varnish

Varnish Cache is a web accelerator also referred to as an HTTP accelerator. You can install it in front of any server that speaks HTTP and configure it to cache the content. Varnish Cache is really, really fast and will speed up your site. One of the main attributes of Varnish Cache is the flexibility of its configuration language, VCL, which enables you to specify how incoming requests should be dealt with.

Memcached

Memcached is a general-purpose memory object caching system for boosting the load speed of dynamic database-driven sites. It is used to reduce the number of times an external data source (such as a database or API) is read by caching data and objects in RAM. The Memcached memory object caching system uses a client/server architecture. The Memcached memory caching system is used by some of the most traffic-hungry sites on the web and is supported by popular web apps like Joomla and WordPress.

Node.js

Node.js is a software system for building scalable network applications. Written in JavaScript, Node.js uses an event-based, non-blocking I/O model that makes it lightweight and effective, suitable for real-time data-rich apps. Node.js uses Google's V8 JavaScript engine, libUV, and several in-built libraries.

InnoDB

InnoDB is the default database engine for the MySQL open-source RDBMS. A storage engine is the principal software component that a DBMS uses to create, retrieve, update and delete data from a database. Its latest release features significant improvements in efficiency, reliability and usability. InnoDB provides the standard ACID-compliant transaction attributes, as well as declarative referential integrity support. It is included as standard in most binary distributions from MySQL AB.