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 the HTTP protocol and configure it to cache the content. Varnish Cache is really, really fast and will increase the speed of your site. One of the major advantages of Varnish Cache is the flexibility of its configuration language, VCL, which enables you to specify how incoming requests should be handled.

Memcached

Memcached is a general-purpose distributed memory object caching system for increasing the loading speed of dynamic database-driven 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 distributed memory caching system uses a client/server architecture. The Memcached system is employed by some of the most traffic-heavy sites on the web and is supported by popular web apps like Joomla and WordPress.

Node.js

Node.js is a platform for writing highly scalable Internet apps. Built on Chrome's JavaScript runtime, Node.js uses an event-based, non-blocking I/O model that makes it lightweight and efficient, great for high-performance data-intensive apps. Node.js uses Google's V8 JavaScript engine, libUV, and several built-in 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 DBMS uses to create, read, modify and delete data from a database. Its latest edition features significant improvements in efficacy, reliability and usability. InnoDB offers the standard ACID-compliant database transaction properties, as well as referential integrity support. InnoDB is included by default in most binary distributions from MySQL AB.