# How to add a custom "tag" to markdown

**URL:** <https://www.ruby-forum.com/t/how-to-add-a-custom-tag-to-markdown/183472>\
**Category:** Ruby\
**Created:** [February 15, 2010, 9:27am UTC](https://www.ruby-forum.com/t/how-to-add-a-custom-tag-to-markdown/183472 "2010-02-15T09:27:53Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![James\_Tippett](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/9fc29f/32.png) [@James\_Tippett](https://www.ruby-forum.com/u/James_Tippett)\
**Post date:** [February 15, 2010, 9:27am UTC](https://www.ruby-forum.com/t/how-to-add-a-custom-tag-to-markdown/183472/1 "2010-02-15T09:27:53Z")

</div>

Hi list,

In a project I need to add some kind of custom “tag” to markdown which  
will be pre-processed by the application. In an otherwise normal bit of  
markdown text (a news posting), I would like to be able to refer to  
other posts, whose URL and description, etc, will be looked up by the  
app and added. It might look something like this:

article:12345

the application would see that text in the post, look up what article  
12345 is, and replace the reference with a link as appropriate.

What would be the best way to achieve this? Some sort of preprocessing?  
Or is there an easy/elegant way to extend Markdown to support this kind  
of thing “natively”?

thanks for any suggestions,

James