Eero Hermlin

Native, lightweight, super-fast plugin for updating comments in real-time with Ajax, without need to refresh the page. Allows comments section work interactively like a chatroom. Comments re-classified as trash or spam will be dynamically removed from users screen. It’s pure WordPress plugin, no need for third parties (like Disqus), no paid services, no secondary logins. Perfect alternative to Disqus.
Administrator can choose update frequency, define in what pages realtime comments are used, comments ordering in selected pages. Additionally is possible to set custom walker function (if used theme uses it) and size of avatar.
Supports also paginated view of comments: in this case new top-level comments will be dynamically are added to newest comments page. Nested comments will be dynamically added to parent comments at any comments page.

Realtime Comments

Accepted comments from users are added to pages in real-time, without need to refresh. Makes comments section work interactively, like a chatroom.

Clement Decou

Used for developer or non developer with a Mercure server configured.
The plugin permit to send notification for the current visitor of your site. 
One feature is to send notification of a current reader of your post to notify that there is a new version of the post content. The user click to the notification and the post content updated in real time.

WP Mercure

Add WordPress integration of Mercure protocol and add realtime post modification.

Realtime Comments vs WP Mercure