QR codes (Quick Response code)

A QR code (Quick Response code) is a type of matrix barcode (or two-dimensional code). 
It is designed to be read by smartphones. Once it is in cell phone, it may give details about that business or product.
The code consists of black modules arranged in a square pattern on a white background.

The information encoded may be text, a URL, or other data.

Features:

They are more useful than a standard bar code, as they can store much more data, including url links, geo coordinates, and text.
The other key feature of QR Codes is that instead of requiring a chunky hand-held scanner to scan them, many modern cell phones can scan them.

Generate a QR code
Generating QR via Google in three steps:
1- Click here http://goo.gl/
2 -Copy paste your information URL in there.
3- For getting QR code click on detail link.

Here you get QR code & its detail.

Regards

Web Services Via Apis

Web service: [A software system designed]

A Web service (also Web Service) is defined by the W3C as "a software system designed to support interoperable machine-to-machine interaction over a network".

API: [An application programming interface]

An application programming interface (API) is a set of routines, data structures, object classes and/or protocols provided by libraries and/or operating system services in order to support the building of applications.

Q: So all web services are API but not all API's a webservice?

Yes, APIs can be libraries such as DLLs, JARs or OCX etc.

They can also be a source code distribution such as Facebooks' PHP api...

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An webservice IS a API over HTTP. They often utilize JSON or XML,

but there are some other approaches as well.

Examples:

Examples of web services specifically see SOAP, REST, and XML-RPC

Example of another type of API, one written in C for use on a local machine, see the Linux Kernel API

Note: web service is a type of API. OR Web service as a web api.

courtesy of Wikipedia and http://stackoverflow.com