Varnish

Varnish Cache is a web application accelerator also known 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 content. Varnish Cache is really, really fast and will increase the loading speed of your web site. One of the main attributes of Varnish Cache is the flexibility of its domain-specific language, VCL, which allows you to define how incoming requests should be tackled.

Memcached

Memcached is a generic distributed memory object caching system for speeding up dynamic database-driven sites. It is used to lower 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 caching system uses a two-tier architecture. The Memcached memory object caching system is used by some of the most popular web sites on the World Wide Web and is supported by popular CMSs like Joomla and WordPress.

Node.js

Node.js is a platform for writing highly scalable Internet applications. Written in JavaScript, Node.js uses an event-driven, non-blocking I/O model that makes it lightweight and efficient, excellent for real-time data-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 database management system. A storage engine is the underlying software component that a DBMS uses to create, retrieve, modify and delete data from a database. Its latest version features significant improvements in performance, security and usability. InnoDB provides the standard ACID database transaction properties, as well as referential integrity support. InnoDB is included by default in most binaries distributed by MySQL AB.