Varnish HTTP Purge is a plugin that sends a purge request to the URL of a post or page every time it is modified. On most themes it is usually preinstalled and activated.
Varnish HTTP Purge
Varnish is a web accelerator / HTTP reverse proxy. It caches your files to reduce the response time and optimize the network bandwidth consuption on future equivalent requests.
Varnish HTTP Purge sends a purge request every time your posts or pages are modified, i.e. when editing, publishing, commenting or deleting an item, and when changing themes.
How to use
Depending on your Varnish configuration, your pages may or may not be purged automatically when modified.
If you want to manually purge the cache of your entire site, click the Purge Varnish button on the WordPress admin toolbar. The purge process will be initiated.
You will be notified when the cache is purged.