Code Syntax Block


Code Syntax Block extends the WordPress block editor by adding syntax highlighting support to the core code block using the Prism syntax highlighter.

The Prism syntax highlighter runs JavaScript loaded on the front-end to parse code blocks and apply syntax markup. A CSS file specifies the color and style to apply to that markup. See Prism syntax highlighter for full details.

Primary development and issues tracked on Github at:


  • Example Syntax Highlighting
  • In Editor Example


After installing and activating the plugin, use in the Block Editor by creating a standard code block and selecting a language format.

When creating a new code block, select Code block, and then in the Inspector (Block Controls on the Right) select the language for the code. The code will not change within the editor, but you’ll see a small label with the selected language.

On the front-end when the post is being viewed, the code will be color syntax highlighted.


What languages are supported?

The Code Syntax Block plugin uses the Prism autoloader plugin to support all of the languages Prism supports. See the list of supported languages here.

How to customize the color scheme?

The default color theme is A11y Dark optimized for accessibility. If you want to change the colorscheme, you can select from the plugin settings page a few different themes shipped with the plugin. You can also use a theme from the Prism themes repo or create your own.

The color theme is a single CSS file, there are a couple ways to customize:

  1. The plugin will check the current theme for the file: assets/prism/prism.css and use that file if it exists. Add your custom file in that location, and it will be used.

  2. If you do not like that file location, you can use the filter mkaz_prism_css_path and specify a path relative to your theme to use.

  3. If you would prefer specifying a full URL, you can use the filter mkaz_prism_css_url and specify a full URL to the stylesheet to use.

An example adding a filter to change the URL, add the following to your theme’s function.php

add_filter( 'mkaz_prism_css_url', function() {
    return '';


Note: if you use the title/filename feature and customize the CSS, you will need to apply your own style targeting the prism-titlename class.

How to customize the language list?

Use the filter mkaz_code_syntax_language_list to customize the list of languages to select displayed in the editor. By default the code syntax block shows a shorter list of popular languages, but Prism supports close to 200, see list.

Use this filter to extend to support the languages you need. Additionally you can use the filter to shorten the list to just the languages you use to make it easier to select.

Here is an example shortening the list to a smaller set:

add_filter( 'mkaz_code_syntax_language_list', function() {
    return array(
        "bash" => "Bash",
        "go" => "Go",
        "html" => "HTML",
        "javascript" => "JavaScript",
        "json" => "JSON",
        "markdown" => "Markdown",
        "php" => "PHP",
        "python" => "Python",
        "jsx" => "React JSX",
        "sass" => "Sass",
        "sql" => "SQL",
        "svg" => "SVG",
        "toml" => "TOML",
        "vim" => "vim",
        "xml" => "XML",
        "yaml" => "YAML",
} );

Can I set a default language so I don’t have to select each time?

Yes, on the plugin settings page in the dashboard you can set a default language when inserting a code block. You can still change if you wish to show code not using the default language.

Can I override the conditional loading, so assets always load?

Yes, use the filter mkaz_code_syntax_force_loading to force always loading assets, otherwise it users has_block to check.


add_filter( 'mkaz_code_syntax_force_loading', '__return_true' );


June 18, 2024
The main thing is that it extends the standard gutenberg block by adding themes. It might be worth adding a button to copy content to clipboard. Good work!
September 19, 2023
Colourise syntax of existing code blocks – great! Wonderful simple options of setting a default theme (e.g. dark/light) and a default code type (e.g. PHP). Just what I was looking for, thanks! Happily working on WordPress 6.3.1 Sept 2023.
June 15, 2022
This is a great plugin – exactly what I was looking for! Thanks so much! Also works with this plugin for copy functionality
Read all 46 reviews

Contributors & Developers

“Code Syntax Block” is open source software. The following people have contributed to this plugin.


“Code Syntax Block” has been translated into 8 locales. Thank you to the translators for their contributions.

Translate “Code Syntax Block” into your language.

Interested in development?

Browse the code, check out the SVN repository, or subscribe to the development log by RSS.

Change log

= 3.2.1

  • Update CSS to reduce specificity, enabling theme.json to override.
    Props to @anlino

= 3.2.0

  • Fix issue with content attributes preserving white space
    Thanks to @chandan-tudu

= 3.1.1

  • Fix trailing comma error, PHP 7

= 3.1.0

  • Add plugin settings page
  • Move global scheme setting to settings
  • Move default language to settings
  • Ugrade Prism to v1.28.0

= 3.0.0

  • Remove support pre WP 5.6
  • Editor view: Show dark background
  • Editor view: Show labels above code block
  • Publish view: Fix line number alignment
  • Publish view: Remove border from code Twentytwentytwo
  • Chore: Update dependencies

= 2.2.0

  • Upgrade Prism to v1.25.0


  • Fix undefined index error with $tag[‘code’] not defined
    on archive page triggered by Beaver Builder


  • Fix background color not being applied unless language specified.
  • Fixes issues with white text on light background.
  • Applies color syntax to all code blocks, language not required


  • Fix pasting plain text stripping elements
  • Removing formating tools that did not work


Compatibility fixes with TwentyTwentyOne theme
– Fixes default text when dark mode enabled
– Fixes linenumbers


Update package dependencies


Fix alignment with Twenty Twenty theme


Upgrade Prism to 1.22
Add Color Scheme options
Fix for WP 5.6 / GB 9.2


Update Prism language components
Adds new language support


Add Rust to default language list
Fix CSS issue with title
Upgrade Prism to 1.21


Fix setting default language using filter.


Fix block validation error for user roles with restricted permissions.


Fix issue with PHP warning when no posts


Fix compatibility issue with Gutenberg plugin 7.9
Removes in editor syntax preview added in 1.3.0


Upgrade Prism to 1.19
Add syntax preview in editor


Add filter to force loading assets, regardless of has_block


Conditionally load asset if has_blocks
Move Hack to front of default font list
Remove !important from font declaration
Change default font size to 15px for usability


Fix alignment issue with TwentyTwenty


Add Java and Kotlin to default language list


Upgrade Prism to 1.17.1


Add filters for customizing language list, and default language.

See full Release Notes on Github releases page