Varnish

Varnish Cache is a web accelerator also referred to as an HTTP accelerator. You can install it in front of any server that speaks the HTTP protocol and configure it to cache the contents. Varnish Cache is very, very fast and will speed up your website. One of the important strengths of Varnish Cache is the flexibility of its domain-specific language, VCL, which allows you to choose how incoming requests should be handled.

Memcached

Memcached is a general-purpose distributed memory 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 database or API) is read by caching data and objects in RAM. The Memcached system uses a client/server architecture. The Memcached system is employed by some of the most traffic-hungry sites on the web and is supported by popular web applications like Joomla and WordPress.

Node.js

Node.js is a software platform for writing highly scalable Internet apps. Built on Chrome's JavaScript runtime, Node.js uses an event-driven, non-blocking input/output model that makes it lightweight and effective, excellent for real-time content-heavy apps. Node.js uses Google's V8 JavaScript engine, libUV, and a number of built-in libraries.

InnoDB

InnoDB is the default database engine for the MySQL open-source RDBMS. 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 release of InnoDB features serious improvements in performance, dependability and functionality. InnoDB provides the standard ACID-compliant transaction attributes, as well as referential integrity support. InnoDB is included by default in most binary distributions from MySQL AB.