John Godley

Sniplets is a generic text insertion plugin with support for an extensible processing framework. At it’s simplest this means you can dynamically replace text in your posts with text that may be defined elsewhere, or created by some other module. For example, you can use Sniplets to perform syntax highlighting of files, execute custom PHP code, insert data from a database, and perform all manner of other useful tasks within a standard interface.
<ul>
<li>Replace tags in a post with pre-defined text</li>
<li>Apply processing functions to the pre-defined text to perform additional functionality</li>
<li>Automatic insertion – data can be made to automatically appear in various places (header, footer, before post, after post, more tag, initialization)</li>
<li>Custom processors can be written by the user</li>
<li>Fully localized</li>
</ul>
Sniplets is available in:
<ul>
<li>English</li>
<li>Belorussian thanks to Marcis Gasuns</li>
</ul>
<h3>Documentation</h3>
Full documentation can be found on the <a href="http://urbangiraffe.com/plugins/sniplets/" rel="nofollow ugc">Sniplets</a> page.

Sniplets

Sniplets is a generic text insertion plugin.  Use it to manually or automatically insert data, PHP, syntax highlight, and almost anything else!

YAHMAN

ZIPANG

When you enter the HTML code directly, the layout changes depending on the p and br tags that WordPress automatically inserts.
<pre><code>remove_filter( 'the_content', 'wpautop' );
</code></pre>
It can be solved by adding the above code. 
However, this will disable all auto-inserted p and br tags. 
It is not user-friendly.
This plugin can be partially disabled.
Just enter the part you want to disable in the shortcode.
<pre><code>[jo]your HTML code[/jo]
</code></pre>
The author of this plugin loves text editors.

Just Output

WordPress automatically inserts p and br tags, but disables them in shortcodes.

Sniplets vs Just Output