edckwt

This plugin enables you to fetch the contents of your site in JSON format by REST API 
Such as sections, articles and search results 
and return it as json 
To be able to use it in your applications or other sites
Endpoints
<ol>
<li>recent posts</li>
<li>posts</li>
<li>search</li>
<li>categories</li>
<li>category</li>
</ol>
For develpoers
<ul>
<li>/api/get_category_posts?type={string}&slug={string}&id={int}&count={int}&page={int}</li>
<li>/api/get_category_index</li>
<li>/api/get_search_results?type={string}&count={int}&page={int}</li>
<li>/api/get_recent_posts?type={string}</li>
<li>/api/get_posts?type={string}&cat={int}&count={int}&page={int}</li>
</ul>
Parameters
<ol>
<li>slug : {string} default: empty post slug</li>
<li>id : {int} default: empty post id</li>
<li>count: {int} default: 5 data display limit</li>
<li>page : {int} default: 1 data display offset</li>
<li>type : {string} default: post post_type</li>
</ol>

EDC REST API

Fetch the content of the sections and articles and search them through the API

Andr&eacute; Boekhorst

This plugin combines the two of the best WordPress plugins: <a href="https://wordpress.org/plugins/advanced-custom-fields/" title="Advanced Custom Fields" rel="ugc">Advanced Custom Fields</a> and <a href="https://wordpress.org/plugins/json-rest-api/" title="WP REST API" rel="ugc">WP REST API</a>.
This plugin is based on the work from<a href="https://github.com/PanManAms/WP-JSON-API-ACF" title="Panman on Github" rel="nofollow ugc">Panman on Github</a>. He was right when he said it would be better as plugin, but it would be even better if it would be available through the WordPress Plugin Repository.
An addition made to this plugin is that each ACF Field van be filtered throug the hook: JSON_META_ACFFIELDNAME (where ACFFIELDNAME depends on the fieldname you’ve added in the Advanced Custom Fields backend.)

WP REST API Custom Fields

The plugin is installed but nothing is in the output of API

JUst does not work

Shows Advanced Custom Field output to the WP REST API for posts, pages, taxonomies and users.

EDC REST API vs WP REST API Custom Fields