Varnish

Varnish Cache is a web application accelerator also famous 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 the loading speed of your web site. One of the chief merits of Varnish Cache is the flexibility of its principal configuration mechanism, 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 speed of dynamic database-driven websites. It is used to decrease 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 two-tier architecture. The Memcached memory object caching system is used by some of the most traffic-heavy web sites on the Internet and is supported by popular Content Management Systems like Joomla and WordPress.

Node.js

Node.js is a platform for building scalable Internet applications. Built on Chrome's JavaScript runtime, Node.js uses an event-driven, non-blocking I/O model that makes it lightweight and efficient, great for real-time content-rich Internet applications. Node.js uses Google's V8 JavaScript engine, libUV, and several built-in libraries.

InnoDB

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