Varnish

Varnish Cache is a web application accelerator also popular as a caching HTTP reverse proxy. You can install it in front of any server that speaks the HTTP protocol and configure it to cache the content. Varnish Cache is really, really fast and will boost your web site's loading speed. One of the important pluses of Varnish Cache is the flexibility of its principal configuration mechanism, VCL, which allows you to choose how incoming requests should be handled.

Memcached

Memcached is a general-purpose distributed memory caching system for boosting the loading speed of dynamic database-driven websites. 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 distributed memory caching system uses a client/server architecture. The Memcached distributed memory caching system is employed by some of the most popular sites on the web and is supported by popular CMSs like Joomla and WordPress.

Node.js

Node.js is a software platform for writing scalable network apps. Built on Chrome's JavaScript runtime, Node.js uses an event-based, asynchronous I/O model that makes it lightweight and efficient, great for high-performance content-intensive applications. 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 principal software component that a database management system uses to create, retrieve, modify and delete data from a database. Its latest release features significant improvements in efficacy, stability and usability. InnoDB offers the standard ACID database transaction attributes, as well as foreign key support. InnoDB is included by default in most binary distributions from MySQL AB.