Varnish

Varnish Cache is a web accelerator also referred to 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 contents. Varnish Cache is very, very fast and will improve your website's speed. One of the chief virtues of Varnish Cache is the flexibility of its domain-specific language, VCL, which enables you to define how incoming requests should be dealt with.

Memcached

Memcached is a generic memory caching system for increasing the load speed of dynamic database-driven sites. It is used to decrease 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 memory object caching system uses a two-tier architecture. The Memcached memory caching system is used by some of the most regularly visited sites on the web and is supported by famous CMSs like Joomla and WordPress.

Node.js

Node.js is a software platform for writing highly scalable network applications. Built on Chrome's JavaScript runtime, Node.js uses an event-based, non-blocking input/output model that makes it lightweight and effective, perfect for real-time content-intensive Internet 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 storage engine is the main software component that a database management system uses to create, retrieve, update and delete data from a database. Its latest release features serious improvements in efficacy, reliability and usability. InnoDB offers the standard ACID-compliant transaction features, as well as declarative referential integrity support. It is included by default in most binary distributions from MySQL AB.