<h4>Why this plugin exists</h4>
Original Plugin (discontinued): https://de.wordpress.org/plugins/json-ld-for-article/
Sadly, the original plugin is not being developed anymore. So I decided to fix some bugs like invalid markup, 
 missing tags, putting objects into fields instead of just URLs for images, and implementing for more than just 
 articles.
Also, this plugin plays nicely with <a href="https://de.wordpress.org/plugins/yet-another-stars-rating/" rel="nofollow ugc">YASR – yet another star rating</a>. It will 
remove yasr’s invalid jsonld-syntax and instead use YASRs rating.
All requests are being cached and purged on page update/edit etc.
<a href="https://waffle.io/bmhm/wp-jsonld" rel="nofollow ugc"></a>
<h4>Original description</h4>
Search engines such as Google are using structured data markup in many ways—for example, to create rich snippets in search results. Search results with rich snippets will improve your click through rates and increase the number of visitors on your website.
It has been a tedious task to add the complicated Schema.org markup to your website – sometimes it wasn’t even possible due to technical constraints. Now, thanks to JSON-LD, almost any website can enjoy the benefits of structured data. For WordPress users it’s even easier thanks to this plugin.
JSON-LD for Article is simply the easiest solution to create valid schema.org microdata markup on your WordPress site automatically from your web content and its metadata. All you need to do is install and activate the plugin, and it will generate JSON-LD markup of your posts that Google and other search engines can use for rich snippets using the schema.org for articles.
Some WP themes include traditional schema.org markup embedded in the html code the theme produces. If you are using one of these themes, this plugin is probably not necessary. If the markup produced by the theme contradicts the data specified in the JSON-LD, the added information might be not be helpful at all. Thus you should check the markup provided by the theme before adding possibly unnecessary JSON-LD to your site.
On the other hand, if you use a custom theme, it is easier to use the functionality provided by the plugin than to invent the wheel again and add the markup in html. Very often, this leads to html code that is difficult to read and is not valid structural markup according to Google’s validator.
Our plugin:
<ul>
<li>Helps your site to earn rich snippets in Google’s SERP.</li>
<li>Does not depend on other plugins or external code.</li>
<li>Is simple to install: plug-and-play, no need to configure anything.</li>
</ul>

wp-jsonld

wp-jsonld is the continuation of the simplest solution to add valid schema.org microdata as JSON-LD-script to your blog posts and articles.

jesucarr

The main reason for the development of this plugin was the lack of options supporting the HTML5 recommendation, where the code snippets should be tagged with <code>pre</code> followed by <code>code</code>, and optionally a class starting with <code>language-</code> and then our language.
You can use the plugin like this:
<pre><code><pre class="prettyprint"><code class="language-php">
// my code
</code></pre>
</code></pre>
Also very important is that although this plugin loads different files depending on your configuration, it fully supports caching scripts (<a href="https://wordpress.org/extend/plugins/w3-total-cache/" rel="ugc">W3 Total Cache</a>) to concatenate and compress all the css and js, so the impact in performance will be minimum.
<h4>Languages</h4>
This syntax highlighter is based on <a href="http://google-code-prettify.googlecode.com/svn/trunk/README.html" rel="nofollow ugc">Google Code Prettify</a> and should work on a number of languages including C and friends, Java, Python, Bash, SQL, HTML, XML, Javascript, Makefiles, and Rust. It works passably on Ruby, PHP, VB, and Awk and a decent subset of Perl and Ruby, but, because of commenting conventions, doesn’t work on Smalltalk.
Other languages are supported via an extension (plugin options): CSS, SQL, YAML, Visual Basic, Clojure, Scala, Latek (TeX, LaTeX), WikiText, Erlang, Go, Haskell, Lua, OCAML, SML, F#, Nemerle, Protocol Buffers, CHDL (VHDL), XQ (XQuery), Lisp, Scheme, Dart, Llvm, Mumps, Pascal, R, S, RD, TCL
<h4>Styles</h4>
Four different styles are provided, and they can be previewed in the plugin options. They are modified to make sure they don’t clash with any other styles in your theme.
You have also the option to include your custom style.
If you have a style that would like to see included in the option list, just <a href="http://www.frontendmatters.com/contact/" rel="nofollow ugc">contact me</a>, or <a href="https://github.com/jesucarr/wordpress-prettify-code-syntax" rel="nofollow ugc">fork me</a>.
<h4>Notes</h4>
<ul>
<li>
Plugin options are at Settings > Prettify Code Syntax. Have a look at the Screenshots tab to see how it looks like.
</li>
<li>
If you don’t care too much about the HTML5 recommendation, you can skip the <code>language-</code> class. The code always gets detected automatically.
</li>
<li>
It will also work if you only use a <code>pre</code> tag without the <code>code</code> tag (but long lines will be wrapped instead of get horizontal scroll), or if you only use a <code>code</code> tag with the <code>prettyprint</code> class (but if you don’t use <code>pre</code> your spaces/returns won’t be maintained.)
</li>
<li>
Be careful using the Visual Editor tab when inserting code, as some HTML tags will be modified or removed.
</li>
<li>
Using a chaching plugin like W3 Total Cache is highly recommended.
</li>
</ul>
<h4>Demo</h4>
You can find a <a href="http://www.frontendmatters.com/open-source/wordpress-plugins/prettify-code-syntax/" rel="nofollow ugc">front end demo</a> here a the bottom.

Prettify Code Syntax

Code syntax highlighter using Google Prettify, supporting the HTML5 recommendation, and caching plugins.

wp-jsonld vs Prettify Code Syntax