Fredrik Stigsson

This plugin uses <a href="https://github.com/googlearchive/code-prettify" rel="nofollow ugc">Google Code Prettify</a> with customized styling. This plugin uses the default skin, custom styling has been applied to show line numbers and to prevent line-breaks. The wp-code-block is styled by the theme (borders, background color and more), the contents of the pre-block is styled by css in the plugin.

Annytab Code Prettify

A lightweight plugin that automatically prettifies code in [pre] tags, with linenumbers and without line-breaks.

anilpeter75

This plugin adds a “JSON Formatter” tool under the Tools menu in your WordPress admin. It allows you to quickly paste unformatted JSON, click a button, and get beautified, validated output without leaving your site.
For more information or to use the original web-based tool, please visit the <a href="https://formatjsononline.com/" rel="nofollow ugc">official website</a>.

Format JSON Online

A simple tool to format and validate JSON online within your WordPress admin.

Annytab Code Prettify vs Format JSON Online