Varnish

Varnish Cache is a web application accelerator also popular 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 increase the speed of your site. One of the important merits of Varnish Cache is the flexibility of its domain-specific language, VCL, which allows you to specify how incoming requests should be tackled.

Memcached

Memcached is a general-purpose distributed memory caching system for speeding up dynamic database-powered 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 memory caching system uses a client/server architecture. The Memcached system is used by some of the most traffic-intensive web sites on the Internet and is supported by popular Content Management Systems like Joomla and WordPress.

Node.js

Node.js is a software platform for building scalable network apps. Written in JavaScript, Node.js uses an event-driven, non-blocking I/O model that makes it lightweight and effective, perfect for real-time content-heavy Internet applications. Node.js uses Google's V8 JavaScript engine, libUV, and several in-built libraries.

InnoDB

InnoDB is the default storage engine for the MySQL open-source database management system. A database engine is the principal software component that a database management system uses to create, retrieve, update and delete data from a database. Its latest release offers significant improvements in performance, security and functionality. InnoDB offers the standard ACID-compliant transaction attributes, along with declarative referential integrity support. InnoDB is included as standard in most binary distributions from MySQL AB.