Varnish

Varnish Cache is a web accelerator also called as an HTTP accelerator. 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 the loading speed of your web site. One of the essential strengths of Varnish Cache is the flexibility of its configuration language, VCL, which permits you to specify how incoming requests should be handled.

Memcached

Memcached is a general-purpose memory caching system for increasing the speed of dynamic database-driven sites. 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 system uses a client'server architecture. The Memcached memory object caching system is used by some of the most regularly visited websites on the web and is supported by popular web apps like Joomla and WordPress.

Node.js

Node.js is a platform for writing scalable network applications. Written in JavaScript, Node.js uses an event-based, asynchronous I/O model that makes it lightweight and effective, great for real-time content-intensive Internet applications. 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 primary software component that a DBMS uses to create, retrieve, update and delete data from a database. Its latest release features serious improvements in performance, dependability and usability. InnoDB offers the standard ACID-compliant database transaction attributes, along with declarative referential integrity support. InnoDB is included by default in most binary distributions from MySQL AB.