Varnish

Varnish Cache is a web accelerator also known as a caching HTTP reverse proxy. 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 boost your website's loading speed. One of the essential merits of Varnish Cache is the flexibility of its domain-specific language, VCL, which allows you to define how incoming requests should be handled.

Memcached

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

Node.js

Node.js is a platform for building scalable Internet applications. Built on Chrome's JavaScript runtime, Node.js uses an event-driven, non-blocking input/output model that makes it lightweight and effective, great for real-time data-intensive Internet 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 DBMS. A database engine is the principal software component that a DBMS uses to create, retrieve, update and delete data from a database. The latest edition of InnoDB features substantial improvements in efficiency, reliability 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.