Varnish

Varnish Cache is a web application accelerator also popular 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 improve your website's loading speed. One of the main pluses of Varnish Cache is the flexibility of its configuration language, VCL, which allows you to determine how incoming requests should be handled.

Memcached

Memcached is a general-purpose memory object caching system for boosting the loading speed of dynamic database-driven websites. 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 system uses a client/server architecture. The Memcached distributed memory caching system is used by some of the most traffic-intensive web sites on the web and is supported by popular web applications like Joomla and WordPress.

Node.js

Node.js is a software platform for building highly scalable Internet applications. Built on Chrome's JavaScript runtime, Node.js uses an event-based, asynchronous I/O model that makes it lightweight and effective, excellent for real-time data-rich 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 RDBMS. A storage engine is the principal software component that a DBMS uses to create, read, update and delete data from a database. Its latest version offers substantial improvements in efficacy, stability and usability. InnoDB offers the standard ACID-compliant transaction attributes, along with declarative referential integrity support. It is included by default in most binaries distributed by MySQL AB.