Varnish

Varnish Cache is a web accelerator also known 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 very, very fast and will boost the speed of your web site. One of the important advantages of Varnish Cache is the flexibility of its configuration language, VCL, which permits you to determine how incoming requests should be handled.

Memcached

Memcached is a general-purpose distributed memory caching system for boosting the load speed of dynamic database-driven web sites. It is used to reduce 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 distributed memory caching system is employed by some of the most traffic-hungry web sites on the web and is supported by popular web apps like Joomla and WordPress.

Node.js

Node.js is a software platform for writing scalable network apps. Written in JavaScript, Node.js uses an event-based, non-blocking I/O model that makes it lightweight and effective, suitable for high-performance content-rich network applications. Node.js uses Google's V8 JavaScript engine, libUV, and a number of built-in libraries.

InnoDB

InnoDB is the default database engine for the MySQL open-source DBMS. A storage engine is the principal software component that a database management system uses to create, retrieve, update and delete data from a database. Its latest release offers substantial improvements in efficiency, stability and usability. InnoDB provides the standard ACID-compliant transaction features, as well as declarative referential integrity support. InnoDB is included as standard in most binary distributions from MySQL AB.