Varnish

Varnish Cache is a web application accelerator also known as a caching HTTP reverse proxy. You can install it in front of any server that speaks HTTP and configure it to cache the content. Varnish Cache is very, very fast and will make your site load much faster. One of the major pluses 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 general-purpose memory caching system for speeding up dynamic database-driven sites. 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 object caching system uses a two-tier architecture. The Memcached distributed memory object caching system is employed by some of the most traffic-hungry sites on the web and is supported by famous web apps like Joomla and WordPress.

Node.js

Node.js is a platform for writing highly scalable Internet apps. Written in JavaScript, Node.js uses an event-based, asynchronous input/output model that makes it lightweight and effective, excellent for real-time data-intensive applications. 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 relational database management system. A storage engine is the main software component that a database management system uses to create, read, modify and delete data from a database. The latest release of InnoDB features serious improvements in efficiency, stability and functionality. InnoDB provides the standard ACID-compliant database transaction properties, as well as declarative referential integrity support. It is included as standard in most binaries distributed by MySQL AB.