Varnish

Varnish Cache is a web accelerator also known 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 boost your website's speed. One of the important merits 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 object caching system for increasing the loading speed of dynamic database-powered 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 memory caching system uses a client/server architecture. The Memcached distributed memory caching system is employed by some of the most popular web sites on the web and is supported by famous web apps like Joomla and WordPress.

Node.js

Node.js is a software system for building highly scalable Internet applications. Built on Chrome's JavaScript runtime, Node.js uses an event-driven, asynchronous I/O model that makes it lightweight and effective, great for real-time content-heavy Internet 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 relational database management system. A database engine is the principal software component that a DBMS uses to create, read, modify and delete data from a database. The latest version of InnoDB offers substantial improvements in performance, dependability and usability. InnoDB provides the standard ACID database transaction features, as well as foreign key support. It is included as standard in most binary distributions from MySQL AB.