Varnish

Varnish Cache is a web accelerator also referred to as an HTTP accelerator. You can install it in front of any web server that speaks HTTP and configure it to cache the content. Varnish Cache is very, very fast and will improve the speed of your website. One of the main merits of Varnish Cache is the flexibility of its domain-specific language, VCL, which allows 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-driven web sites. It is used to decrease 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 distributed memory caching system uses a client'server architecture. The Memcached memory caching system is employed by some of the most regularly visited sites on the World Wide Web and is supported by popular web apps like Joomla and WordPress.

Node.js

Node.js is a software platform for writing scalable network apps. Written in JavaScript, Node.js uses an event-based, non-blocking I/O model that makes it lightweight and effective, great for high-performance content-intensive apps. Node.js uses Google's V8 JavaScript engine, libUV, and several built-in libraries.

InnoDB

InnoDB is the default storage engine for the MySQL open-source DBMS. A storage engine is the primary software component that a database management system uses to create, retrieve, update and delete data from a database. The latest version of InnoDB offers considerable improvements in performance, stability and usability. InnoDB offers the standard ACID transaction properties, along with declarative referential integrity support. It is included by default in most binary distributions from MySQL AB.