Amit Gupta

iG:Syntax Hiliter allows you to post source code to your site with syntax highlighting and formatting (as seen in code editors, IDEs). You can paste the code as is from your code editor or IDE and this plugin will take care of all the code colouring and preserve your formatting. It uses the <a href="http://qbnz.com/highlighter/" rel="nofollow ugc">GeSHi library</a> to colourize your code and supports over a 100 programming languages. Most common languages are included with the plugin and it includes drop in support for more languages used by GeSHi.
NOTE : For fast results and less load on your server, you should have a cache plugin installed. That way the plugin won’t have to parse the code blocks on a post every time its loaded in browser.
<h4>Minimum Requirements</h4>
<ul>
<li>WordPress 4.1 or above</li>
<li>PHP 7.4.0 or above</li>
</ul>
Pull requests are welcome on Github.
Github: <a href="https://github.com/coolamit/ig-syntax-hiliter/" rel="nofollow ugc">https://github.com/coolamit/ig-syntax-hiliter/</a> 
<a href="https://github.com/coolamit/ig-syntax-hiliter/blob/master/README.md" rel="nofollow ugc">Documentation on plugin usage and configuration</a>

iG:Syntax Hiliter

A plugin to easily present source code on your site with syntax highlighting and formatting  (as seen in code editors, IDEs).

mayel2b

Helps you more effectively edit your themes or plugins when you only have access to a browser, by enabling syntax highlighting in WordPress’ integrated source code editors. Supports PHP, HTML, CSS and JavaScript.
Please provide any feedback at http://anetech.eu/power-code-editor/
Everything is done in JavaScript on the client side.
At this time, the following browsers are supported: 
* Firefox 1.5 or higher 
* Internet Explorer 6 or higher 
* Safari 3 or higher 
* Opera 9.52 or higher 
* Chrome
Licensed under the GNU GPL v2.
Uses the excellent CodeMirror JS library : 
http://marijn.haverbeke.nl/codemirror/

Power Code Editor

Enables syntax highlighting in the integrated source code editors. Supports PHP, HTML, CSS and JS.

iG:Syntax Hiliter vs Power Code Editor