Varnish

Varnish Cache is a web accelerator also popular as an HTTP accelerator. You can install it in front of any server that speaks the HTTP protocol and configure it to cache the contents. Varnish Cache is really, really fast and will improve your website's speed. One of the major merits of Varnish Cache is the flexibility of its configuration language, VCL, which allows you to define how incoming requests should be dealt with.

Memcached

Memcached is a general-purpose distributed memory object caching system for increasing the load speed of dynamic database-driven web sites. It is used to decrease 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 distributed memory caching system is employed by some of the most popular websites on the World Wide Web and is supported by popular web applications like Joomla and WordPress.

Node.js

Node.js is a software platform for building scalable Internet applications. Built on Chrome's JavaScript runtime, Node.js uses an event-based, non-blocking input/output model that makes it lightweight and efficient, excellent for real-time data-heavy apps. 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 database management system. A storage engine is the principal software component that a database management system uses to create, read, update and delete data from a database. Its latest release offers substantial improvements in performance, reliability and functionality. InnoDB provides the standard ACID-compliant database transaction attributes, along with declarative referential integrity support. InnoDB is included as standard in most binary distributions from MySQL AB.