Varnish

Varnish Cache is a web application accelerator also referred to as an HTTP accelerator. 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 very, very fast and will improve your site's speed. One of the key virtues of Varnish Cache is the flexibility of its domain-specific language, VCL, which permits you to choose how incoming requests should be tackled.

Memcached

Memcached is a general-purpose memory caching system for increasing the speed of dynamic database-powered web sites. It is used to decrease 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 caching system uses a client/server architecture. The Memcached system is employed by some of the most popular web sites on the Internet and is supported by popular web applications like Joomla and WordPress.

Node.js

Node.js is a software platform for building highly scalable Internet applications. Written in JavaScript, Node.js uses an event-driven, non-blocking I/O model that makes it lightweight and effective, perfect for real-time content-intensive applications. Node.js uses Google's V8 JavaScript engine, libUV, and a number of in-built libraries.

InnoDB

InnoDB is the default database engine for the MySQL open-source relational database management system. A database engine is the underlying software component that a DBMS uses to create, retrieve, update and delete data from a database. The latest version of InnoDB offers significant improvements in efficacy, security and functionality. InnoDB offers the standard ACID database transaction properties, along with declarative referential integrity support. InnoDB is included as standard in most binaries distributed by MySQL AB.