Varnish

Varnish Cache is a web application accelerator also popular as a caching HTTP reverse proxy. You can install it in front of any web server that speaks HTTP and configure it to cache the content. Varnish Cache is really, really fast and will improve your site's loading speed. One of the major merits of Varnish Cache is the flexibility of its principal configuration mechanism, VCL, which enables you to define how incoming requests should be tackled.

Memcached

Memcached is a generic memory object caching system for increasing the load speed of dynamic database-driven websites. 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 memory object caching system uses a client/server architecture. The Memcached system is used by some of the most frequently visited websites on the Internet and is supported by popular CMSs like Joomla and WordPress.

Node.js

Node.js is a platform for writing highly scalable network apps. Written in JavaScript, Node.js uses an event-driven, non-blocking I/O model that makes it lightweight and efficient, excellent for real-time content-rich applications. Node.js uses Google's V8 JavaScript engine, libUV, and a number of built-in libraries.

InnoDB

InnoDB is the default storage engine for the MySQL open-source RDBMS. A storage engine is the primary software component that a DBMS uses to create, read, update and delete data from a database. The latest edition of InnoDB features substantial improvements in efficacy, security and usability. InnoDB provides the standard ACID transaction properties, along with referential integrity support. InnoDB is included as standard in most binaries distributed by MySQL AB.