Varnish

Varnish Cache is a web accelerator also called as a caching HTTP reverse proxy. You can install it in front of any server that speaks HTTP and configure it to cache the content. Varnish Cache is very, very fast and will increase your site's speed. One of the major features of Varnish Cache is the flexibility of its domain-specific language, VCL, which allows you to specify how incoming requests should be dealt with.

Memcached

Memcached is a general-purpose memory object caching system for boosting the speed of dynamic database-powered 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 two-tier architecture. The Memcached memory object caching system is employed by some of the most frequently visited web sites on the web and is supported by famous web apps like Joomla and WordPress.

Node.js

Node.js is a software platform for writing highly scalable Internet applications. Written in JavaScript, Node.js uses an event-driven, asynchronous I/O model that makes it lightweight and efficient, excellent for real-time data-rich network applications. Node.js uses Google's V8 JavaScript engine, libUV, and a number of built-in libraries.

InnoDB

InnoDB is the default database engine for the MySQL open-source relational database management system. A database engine is the primary software component that a database management system uses to create, read, update and delete data from a database. The latest version of InnoDB features significant improvements in efficacy, stability and usability. InnoDB provides the standard ACID-compliant database transaction attributes, as well as referential integrity support. InnoDB is included by default in most binaries distributed by MySQL AB.