Varnish

Varnish Cache is a web accelerator also famous as an HTTP accelerator. You can install it in front of any server that speaks HTTP and configure it to cache the contents. Varnish Cache is really, really fast and will improve your website's speed. One of the key virtues of Varnish Cache is the flexibility of its domain-specific language, VCL, which allows you to specify how incoming requests should be handled.

Memcached

Memcached is a generic distributed memory caching system for boosting the speed of dynamic database-driven websites. It is used to lower 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 distributed memory caching system uses a two-tier architecture. The Memcached system is used by some of the most regularly visited websites on the web and is supported by famous Content Management Systems like Joomla and WordPress.

Node.js

Node.js is a software system for writing highly scalable network apps. 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 high-performance content-heavy apps. Node.js uses Google's V8 JavaScript engine, libUV, and several in-built libraries.

InnoDB

InnoDB is the default database engine for the MySQL open-source RDBMS. A storage engine is the main software component that a DBMS uses to create, retrieve, modify and delete data from a database. Its latest version features considerable improvements in efficiency, dependability and usability. InnoDB provides the standard ACID transaction features, as well as referential integrity support. InnoDB is included by default in most binaries distributed by MySQL AB.