## Official

* [twitter-extension][1] - Adds support of Twitter usernames and hastags
* [prettify-extension][2] - Adds [Google Prettify][3] hints to HTML output

## Community

* [showdown-icon][4] - Adds support of Glyphicon and font-awesome into Markdown
* [showdown-xss-filter][5] - Filters XSS, using leizongmin/js-xss
* [showdown-toc][6] - Adds Table of Contents
* [showdown-footnotes][7] - Adds simple footnotes
* [katex-latex][8] - Displays math using KaTeX and LaTeX or AsciiMath

!!! note ""
    If you have a Showdown extension you would like to add here, you can [raise an issue](https://github.com/showdownjs/showdown/issues).

[1]: https://github.com/showdownjs/twitter-extension
[2]: https://github.com/showdownjs/prettify-extension
[3]: https://github.com/googlearchive/code-prettify
[4]: https://github.com/dbtek/showdown-icon
[5]: https://github.com/VisionistInc/showdown-xss-filter
[6]: https://github.com/ravisorg/showdown-toc
[7]: https://github.com/Kriegslustig/showdown-footnotes
[8]: https://obedm503.github.io/showdown-katex