Varnish

Varnish Cache is a web application accelerator also referred to as a caching HTTP reverse proxy. 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 really, really fast and will boost the loading speed of your website. One of the important virtues of Varnish Cache is the flexibility of its principal configuration mechanism, VCL, which permits you to determine how incoming requests should be dealt with.

Memcached

Memcached is a general-purpose distributed memory object caching system for increasing the speed of 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 memory caching system uses a two-tier architecture. The Memcached memory caching system is employed by some of the most regularly visited websites on the World Wide Web and is supported by popular CMSs like Joomla and WordPress.

Node.js

Node.js is a platform for writing scalable network apps. Written in JavaScript, Node.js uses an event-based, asynchronous input/output model that makes it lightweight and efficient, excellent for real-time data-intensive Internet apps. Node.js uses Google's V8 JavaScript engine, libUV, and several built-in libraries.

InnoDB

InnoDB is the default database engine for the MySQL open-source relational database management system. A database engine is the underlying software component that a database management system uses to create, retrieve, update and delete data from a database. Its latest release features substantial improvements in efficacy, security and usability. InnoDB offers the standard ACID transaction features, along with foreign key support. InnoDB is included as standard in most binary distributions from MySQL AB.