Varnish

Varnish Cache is a web application accelerator also called as an HTTP accelerator. 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 very, very fast and will improve your site's speed. One of the chief virtues of Varnish Cache is the flexibility of its principal configuration mechanism, VCL, which allows you to determine how incoming requests should be dealt with.

Memcached

Memcached is a general-purpose memory object caching system for increasing the loading speed of dynamic database-driven sites. 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 two-tier architecture. The Memcached memory object caching system is used by some of the most regularly visited web sites on the Internet and is supported by popular CMSs 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-driven, non-blocking input/output model that makes it lightweight and effective, suitable for high-performance content-intensive network apps. Node.js uses Google's V8 JavaScript engine, libUV, and several in-built libraries.

InnoDB

InnoDB is the default database engine for the MySQL open-source DBMS. A database engine is the primary software component that a DBMS uses to create, retrieve, update and delete data from a database. The latest release of InnoDB features considerable improvements in efficacy, stability and usability. InnoDB provides the standard ACID database transaction attributes, along with referential integrity support. InnoDB is included by default in most binaries distributed by MySQL AB.