Varnish

Varnish Cache is a web accelerator also known as an HTTP accelerator. You can install it in front of any server that speaks the HTTP protocol and configure it to cache the content. Varnish Cache is very, very fast and will boost your site's speed. One of the chief attributes of Varnish Cache is the flexibility of its principal configuration mechanism, VCL, which permits you to choose how incoming requests should be dealt with.

Memcached

Memcached is a generic distributed memory object caching system for increasing the speed of dynamic database-driven websites. 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 distributed memory caching system uses a client/server architecture. The Memcached distributed memory object caching system is employed by some of the most popular web sites on the Internet and is supported by famous web apps like Joomla and WordPress.

Node.js

Node.js is a software system for building 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, perfect for real-time content-heavy applications. 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 database management system. A storage engine is the underlying software component that a DBMS uses to create, retrieve, update and delete data from a database. The latest release of InnoDB features serious improvements in efficiency, stability and functionality. InnoDB provides the standard ACID-compliant database transaction properties, as well as foreign key support. It is included by default in most binaries distributed by MySQL AB.