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 HTTP and configure it to cache the content. Varnish Cache is really, really fast and will increase your website's speed. One of the essential features of Varnish Cache is the flexibility of its domain-specific language, VCL, which enables you to determine how incoming requests should be handled.

Memcached

Memcached is a generic memory object caching system for boosting the load speed of dynamic database-driven web 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 client/server architecture. The Memcached distributed memory caching system is employed by some of the most traffic-hungry sites on the web and is supported by popular Content Management Systems like Joomla and WordPress.

Node.js

Node.js is a software system for writing scalable network apps. Written in JavaScript, Node.js uses an event-based, asynchronous I/O model that makes it lightweight and efficient, great for high-performance data-intensive Internet apps. Node.js uses Google's V8 JavaScript engine, libUV, and a number of built-in libraries.

InnoDB

InnoDB is the default database engine for the MySQL open-source relational database management system. A storage engine is the primary software component that a DBMS uses to create, read, update and delete data from a database. Its latest release offers serious improvements in efficiency, security and usability. InnoDB provides the standard ACID-compliant database transaction attributes, as well as foreign key support. It is included as standard in most binaries distributed by MySQL AB.