Varnish

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

Memcached

Memcached is a generic memory object caching system for increasing the speed of dynamic database-driven web sites. It is used to reduce 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 object caching system uses a two-tier architecture. The Memcached distributed memory object caching system is used by some of the most traffic-heavy sites on the Internet and is supported by famous web applications like Joomla and WordPress.

Node.js

Node.js is a software platform for writing scalable network apps. Written in JavaScript, Node.js uses an event-driven, asynchronous input/output model that makes it lightweight and effective, perfect for real-time content-heavy network 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 relational database management system. A database engine is the primary software component that a database management system uses to create, retrieve, update and delete data from a database. The latest version of InnoDB features substantial improvements in performance, reliability and functionality. InnoDB offers the standard ACID database transaction properties, along with declarative referential integrity support. InnoDB is included by default in most binaries distributed by MySQL AB.