Varnish

Varnish Cache is a web application accelerator also called 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 increase your site's speed. One of the chief pluses of Varnish Cache is the flexibility of its domain-specific language, VCL, which allows you to specify how incoming requests should be dealt with.

Memcached

Memcached is a general-purpose memory object caching system for boosting the speed of dynamic database-powered sites. It is used to reduce 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 memory object caching system uses a two-tier architecture. The Memcached distributed memory caching system is employed by some of the most frequently visited sites on the Internet and is supported by popular web apps like Joomla and WordPress.

Node.js

Node.js is a software platform for building highly scalable network applications. Written in JavaScript, Node.js uses an event-based, asynchronous input/output model that makes it lightweight and effective, suitable for real-time content-heavy Internet applications. Node.js uses Google's V8 JavaScript engine, libUV, and several in-built libraries.

InnoDB

InnoDB is the default storage engine for the MySQL open-source database management system. A storage engine is the underlying software component that a database management system uses to create, retrieve, modify and delete data from a database. Its latest version features considerable improvements in efficiency, security and usability. InnoDB offers the standard ACID transaction features, along with declarative referential integrity support. InnoDB is included as standard in most binaries distributed by MySQL AB.