Hinaloe

This plugin allow your site’s comment form makes ajax — non move/reload when user (including both subscriber, normal viewer, and admins too) post comment!
Most themes supports this plugin, but if your theme’s <code>class_form</code> have not <code>comment-form</code>, this plugin non supported.
And this plugin only can use for Pure WordPress Comment form. 
so, its not able to be used with like Jetpack comment form and other original/outside comment system/form.
Feature
<ul>
<li>post comment with ajax</li>
<li>Lite — this plugin only using a little of jQuery feature to modify DOM, and very tiny js & PHP code.</li>
</ul>
Require
You have to install <a href="https://wordpress.org/plugins/rest-api/" rel="ugc">WP REST API v2</a> to use this plugin if your site is running on WP 4.4-4.6.

ajax Post Comment

Post comment form on frontend tobe ajax using WP REST API Version.2

cwdekker

Sekura REST Bridge for ACF securely exposes Advanced Custom Fields in the WordPress REST API. Based on <a href="https://github.com/airesvsg/acf-to-rest-api" rel="nofollow ugc">ACF to REST API</a> by Aires Goncalves, rebuilt with security as a first-class concern.
The original ACF to REST API plugin exposes all ACF field data to unauthenticated requests, including options pages (which often contain API keys and secrets), user profile fields, and fields on private/draft posts. This plugin fixes that with proper WordPress capability checks on every endpoint.
<h4>Features</h4>
<ul>
<li>Proper permission checks on every endpoint</li>
<li>Per-field Show in REST API / Edit in REST API toggles</li>
<li>Works alongside ACF Pro’s native REST support</li>
<li>Drop-in replacement for ACF to REST API (same acf/v3 namespace)</li>
<li>Filterable permissions for custom access control</li>
</ul>
<h4>Endpoints</h4>
<ul>
<li><code>GET /wp-json/acf/v3/{post_type}/{id}</code> – Get ACF fields for a post</li>
<li><code>GET /wp-json/acf/v3/{post_type}/{id}/{field}</code> – Get a specific field</li>
<li><code>PUT /wp-json/acf/v3/{post_type}/{id}</code> – Update ACF fields</li>
<li><code>GET /wp-json/acf/v3/options/{id}</code> – Get ACF options page fields</li>
<li><code>GET /wp-json/acf/v3/users/{id}</code> – Get ACF fields for a user</li>
<li><code>GET /wp-json/acf/v3/comments/{id}</code> – Get ACF fields for a comment</li>
</ul>
ACF data is also appended as an <code>acf</code> key on standard WP REST API responses.

Sekura REST Bridge for ACF

Expose Advanced Custom Fields in the WordPress REST API with proper access control.

ajax Post Comment vs Sekura REST Bridge for ACF