Varnish

Varnish Cache is a web accelerator also referred to as a caching HTTP reverse proxy. You can install it in front of any web server that speaks the HTTP protocol and configure it to cache the contents. Varnish Cache is really, really fast and will improve the speed of your site. One of the main pluses of Varnish Cache is the flexibility of its domain-specific language, VCL, which enables you to determine how incoming requests should be dealt with.

Memcached

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

Node.js

Node.js is a platform for building scalable network applications. Written in JavaScript, Node.js uses an event-driven, non-blocking input/output model that makes it lightweight and effective, excellent for real-time data-rich network apps. Node.js uses Google's V8 JavaScript engine, libUV, and a number of built-in libraries.

InnoDB

InnoDB is the default storage engine for the MySQL open-source RDBMS. A storage engine is the underlying software component that a database management system uses to create, read, update and delete data from a database. Its latest version offers considerable improvements in efficacy, stability and usability. InnoDB offers the standard ACID-compliant transaction features, as well as declarative referential integrity support. It is included by default in most binary distributions from MySQL AB.