Disable the Heartbeat API Except in the Post Editor
Keeps the Heartbeat API (autosave and post locking) in the editor but turns it off on every other admin and front-end page to save server requests.
Snippet Library
Performance snippets for WordPress
Snippets that make WordPress lighter and faster: remove emoji scripts and embeds, control the Heartbeat API, limit revisions and load scripts only where they are needed. For developers and site owners chasing better Core Web Vitals.
Find What Is Calling admin-ajax.php
Counts admin-ajax.php requests per action (and whether they come from the front end or the dashboard) for the current day and the previous six, and shows the busiest ones under Tools > AJAX Usage.