Varnish

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

Memcached

Memcached is a generic memory object caching system for boosting the speed of dynamic database-driven websites. It is used to lower 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 distributed memory object caching system uses a two-tier architecture. The Memcached system is used by some of the most popular sites on the World Wide Web and is supported by popular web apps like Joomla and WordPress.

Node.js

Node.js is a software system for writing scalable network applications. Written in JavaScript, Node.js uses an event-driven, non-blocking input/output model that makes it lightweight and effective, suitable for real-time data-heavy apps. 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 storage engine is the main software component that a database management system uses to create, read, update and delete data from a database. The latest version of InnoDB offers substantial improvements in efficacy, security and functionality. InnoDB offers the standard ACID database transaction attributes, as well as foreign key support. It is included by default in most binary distributions from MySQL AB.