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

Josh Pollock

Provides useful tools for optimizing a WordPress site to power a single page web app using WordPress REST API. Designed to work as a companion for the <a href="https://github.com/shelob9/josie" rel="nofollow ugc">Josie REST API-powered starter app</a> but useful for any site using the WordPress REST API.
This is a companion plugin for my WordPress REST API (WP-API) powered application starter, called <a href="https://github.com/shelob9/josie" rel="nofollow ugc">Josie</a>. It can be used with any site running the <a href="http://wp-api.org/" rel="nofollow ugc">WordPress REST API</a>.
It packages multiple libraries, most of which I wrote, to accomplish several things:
1) <a href="https://github.com/shelob9/jp-rest-cache" rel="nofollow ugc">Provides a soft-expiring, server-side cache for requests to the REST API</a>.
2) <a href="https://github.com/Shelob9/jp-tax-query" rel="nofollow ugc">Adds routes and endpoints for making tax-queries</a>.
3) <a href="https://github.com/Shelob9/jp-menu-route" rel="nofollow ugc">Adds routes and endpoints for getting menus & menu items</a>.
4) <a href="https://github.com/Shelob9/jp-rest-access" rel="nofollow ugc">Adds cross-domain headers, and for the posts endpoint allows for page offsets and limits the number of posts_per_page</a>.

Josie API

Adds endpoints for menus & tax-queries, as well as a server-side cache and CORS headers for the WordPress REST API.

ajax Post Comment vs Josie API