Varnish

Varnish Cache is a web accelerator also popular as a caching HTTP reverse proxy. You can install it in front of any web server that speaks the HTTP protocol and configure it to cache the contents. Varnish Cache is really, really fast and will increase the speed of your site. One of the important advantages of Varnish Cache is the flexibility of its principal configuration mechanism, VCL, which enables you to define how incoming requests should be tackled.

Memcached

Memcached is a generic distributed memory caching system for speeding up dynamic database-driven websites. It is used to reduce 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 object caching system uses a client/server architecture. The Memcached system is used by some of the most traffic-intensive sites on the Internet and is supported by famous Content Management Systems like Joomla and WordPress.

Node.js

Node.js is a platform for writing highly scalable network apps. Written in JavaScript, Node.js uses an event-based, non-blocking I/O model that makes it lightweight and effective, great for high-performance data-heavy network 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 database engine is the principal software component that a database management system uses to create, retrieve, modify and delete data from a database. The latest release of InnoDB features serious improvements in performance, dependability and usability. InnoDB offers the standard ACID-compliant database transaction features, along with declarative referential integrity support. It is included by default in most binaries distributed by MySQL AB.