Varnish

Varnish Cache is a web accelerator also referred to as a caching HTTP reverse proxy. You can install it in front of any server that speaks HTTP and configure it to cache the contents. Varnish Cache is really, really fast and will improve the speed of your website. One of the chief strengths of Varnish Cache is the flexibility of its configuration language, VCL, which permits you to determine how incoming requests should be handled.

Memcached

Memcached is a generic distributed memory object caching system for boosting the speed of dynamic database-powered websites. It is used to reduce the number of times an external data source (such as a database or API) is read by caching data and objects in RAM. The Memcached memory caching system uses a client/server architecture. The Memcached system is used by some of the most traffic-hungry web sites on the web and is supported by popular CMSs like Joomla and WordPress.

Node.js

Node.js is a platform for building highly scalable Internet apps. Built on Chrome's JavaScript runtime, Node.js uses an event-based, asynchronous I/O model that makes it lightweight and effective, great for high-performance data-heavy network applications. Node.js uses Google's V8 JavaScript engine, libUV, and a number of in-built libraries.

InnoDB

InnoDB is the default database engine for the MySQL open-source relational database management system. A storage engine is the main software component that a database management system uses to create, read, update and delete data from a database. The latest edition of InnoDB features considerable improvements in efficiency, stability and functionality. InnoDB provides the standard ACID transaction attributes, along with declarative referential integrity support. InnoDB is included as standard in most binary distributions from MySQL AB.