Varnish

Varnish Cache is a web accelerator also called 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 really, really fast and will increase your site's loading speed. One of the major strengths of Varnish Cache is the flexibility of its configuration language, VCL, which allows you to specify how incoming requests should be handled.

Memcached

Memcached is a generic distributed memory object caching system for increasing the load speed of dynamic database-driven 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 object caching system is used by some of the most popular websites on the web and is supported by popular web apps like Joomla and WordPress.

Node.js

Node.js is a software system for building scalable network applications. Built on Chrome's JavaScript runtime, Node.js uses an event-based, non-blocking input/output model that makes it lightweight and effective, perfect for high-performance data-heavy network apps. 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 database engine is the underlying software component that a DBMS uses to create, read, update and delete data from a database. The latest edition of InnoDB offers significant improvements in performance, dependability and usability. InnoDB provides the standard ACID-compliant database transaction properties, as well as referential integrity support. InnoDB is included as standard in most binaries distributed by MySQL AB.