Varnish

Varnish Cache is a web application accelerator also called as a caching HTTP reverse proxy. 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 site's speed. One of the important advantages 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 memory object caching system for speeding up dynamic database-driven websites. It is used to lower 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 caching system uses a client/server architecture. The Memcached system is employed by some of the most traffic-heavy web sites on the Internet and is supported by famous CMSs like Joomla and WordPress.

Node.js

Node.js is a platform for writing scalable Internet applications. Written in JavaScript, Node.js uses an event-based, non-blocking I/O model that makes it lightweight and effective, suitable for real-time data-intensive apps. Node.js uses Google's V8 JavaScript engine, libUV, and several built-in libraries.

InnoDB

InnoDB is the default database engine for the MySQL open-source database management system. A storage engine is the primary software component that a DBMS uses to create, retrieve, modify and delete data from a database. Its latest version features substantial improvements in performance, security and functionality. InnoDB offers the standard ACID database transaction properties, along with declarative referential integrity support. It is included as standard in most binary distributions from MySQL AB.