Varnish

Varnish Cache is a web application accelerator also famous as a caching HTTP reverse proxy. You can install it in front of any server that speaks HTTP and configure it to cache the content. Varnish Cache is very, very fast and will improve your web site's speed. One of the main pluses of Varnish Cache is the flexibility of its domain-specific language, VCL, which permits you to define how incoming requests should be dealt with.

Memcached

Memcached is a generic distributed memory caching system for boosting the load speed of dynamic database-driven web sites. It is used to lower 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 system uses a client/server architecture. The Memcached memory caching system is used by some of the most regularly visited web sites on the Internet and is supported by popular web applications like Joomla and WordPress.

Node.js

Node.js is a platform for building highly scalable Internet applications. Built on Chrome's JavaScript runtime, Node.js uses an event-driven, non-blocking I/O model that makes it lightweight and effective, suitable for real-time data-rich apps. Node.js uses Google's V8 JavaScript engine, libUV, and several in-built libraries.

InnoDB

InnoDB is the default storage engine for the MySQL open-source database management system. A database engine is the principal software component that a DBMS uses to create, retrieve, update and delete data from a database. The latest version of InnoDB offers substantial improvements in performance, security and usability. InnoDB offers the standard ACID transaction features, along with referential integrity support. It is included by default in most binaries distributed by MySQL AB.