RobertoAlicata

Usage:
write [qrcode] to generate a QRcode for the actual url with size of 100×100 pixels
you can specify these attributes:
size (it indicates the size in pixels for width and height, default: 100)
alt (it indicates the alternative text for the image: default “scan QR code”)
content (leave it blank to pass the actual url or write the content to encode)
click (write “yes” to make the image clickable)
fgcolor (foreground color in hexadecimal format)
bgcolor (background color in hexadecimal format)
example: [qrcode size=200 content=”www.robertoalicata.it” alt=”scan me NOW” click=”yes”]

ra_qrcode

a simple WordPress plugin to generate a QR code with a configurable shortcode and Widget

jweblog

Use this QRCode Generator wordpress plugin to create a image QRCode on any site of your WordPress installation. Use a shortcode in your posts to insert dynamic, customizable posts, pages, images, or attachments based on categories and tags. Visite http://qrcode.jar.io for more information.
The shortcode [qrcode] within your site to generate a qr code including the URL of the current site. This plugin is offered freely by QRCode Generator API Online [qrcode.jar.io].
If you find this plugin useful, please rating this plugin on [https://wordpress.org/extend/plugins/api-qrcode-generator/]
Check website for live demo [http://yoga.jar.io/]
How to use:
<ul>
<li>
Use the shortcode [qrcode] within your site to generate a qr code including the URL of the current site
</li>
<li>
Use the fullowing short code to generate a indivdual qr code with any text content: 
[qrcode content=”text” size=”150px” alt=”text” class=”text”]
</li>
</ul>
<h3>Author</h3>
Jweblog 
“Programming usefull codes for good internet!” 
(http://github.com/jweblog “WP-QRCode Generator”)

API QRCode Generator

Use QRCode Generator to create a image QRCode on any site of your blog.

ra_qrcode vs API QRCode Generator