Varnish

Varnish Cache is a web application accelerator also called as an HTTP accelerator. You can install it in front of any server that speaks HTTP and configure it to cache the content. Varnish Cache is really, really fast and will boost your site's speed. One of the important attributes of Varnish Cache is the flexibility of its domain-specific language, VCL, which allows you to choose how incoming requests should be dealt with.

Memcached

Memcached is a general-purpose distributed memory object caching system for boosting the loading speed of dynamic database-powered web sites. 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 caching system is employed by some of the most traffic-heavy web sites on the web and is supported by popular Content Management Systems like Joomla and WordPress.

Node.js

Node.js is a platform for writing highly scalable network apps. Built on Chrome's JavaScript runtime, Node.js uses an event-based, non-blocking input/output model that makes it lightweight and efficient, great for real-time data-heavy Internet applications. Node.js uses Google's V8 JavaScript engine, libUV, and several in-built libraries.

InnoDB

InnoDB is the default database engine for the MySQL open-source RDBMS. A database engine is the underlying software component that a database management system uses to create, retrieve, update and delete data from a database. The latest version of InnoDB features serious improvements in performance, reliability and functionality. InnoDB provides the standard ACID database transaction features, along with foreign key support. It is included as standard in most binary distributions from MySQL AB.