web services in python be invoked over httphowever this has been extended to provide more rest like facilities in this we will focus on flask as it is one of the most widely used frameworks for light weight restful services in python flask flask is web development framework for python it describes itself as micro framework for python which is somewhat confusingto the point where there is page dedicated to this on their web site that explains what it means and what the implications are of this for flask according to flaskthe micro in its description relates to its primary aim of keeping the core of flask simple but extensible unlike django it doesn' include facilities aimed at helping you integrate your application with database for example instead flask focuses on the core functionality required of web service framework and allows extension to be usedas and when requiredfor additional functionality flask is also convention over configuration frameworkthat is if you follow the standard conventions then you will not need to deal with much additional configuration information (although if you wish to follow different set of conventions then you can provide configuration information to change the defaultsas most people will (at least initiallyfollow these conventions it makes it very easy to get something up and running very quickly hello world in flask as is traditional in all programming languages we will start of with simple 'hello worldstyle application this application will allow us to create very simple web service that maps particular url to function that will return json format data we will use the json data format as it is very widely used within web-based services using json json standards for javascript object notationit is light weight data-interchange format that is also easy for humans to read and write although it is derived from subset of the javascript programming languageit is in fact completely language independent and many languages and frameworks now support automatically processing of their own formats into and from json this makes it ideal for restful web services