Razvan Stanga

Complete WordPress Varnish Cache 3.x/4.x/5.x and Nginx Proxy Cache integration.
This plugin handles all integration with Varnish Cache and Nginx Proxy Cache. It was designed for high traffic websites.
Main features
<ul>
<li>admin interface, see screenshots</li>
<li>console for manual purges, supports regular expressions so you can purge an entire folder or just a single file</li>
<li>supports every type of Varnish Cache implementation, see screenshots for examples</li>
<li>unlimited number of Varnish Cache servers</li>
<li>use of custom headers when communicating with Varnish Cache does not interfere with other caching plugins, cloudflare, etc</li>
<li>Varnish Cache configuration generator</li>
<li>purge key method so you don’t need to setup ACLs</li>
<li>debugging</li>
<li>actively maintained</li>
</ul>
You can control the following from the Varnish Caching admin panel :
<ul>
<li>Enable/Disable caching</li>
<li>Homepage cache TTL</li>
<li>Cache TTL (for every other page)</li>
<li>IPs/Hosts to clear cache to support every type of Varnish Cache implementation</li>
<li>Override default TTL in posts/pages</li>
<li>Purge key based PURGE</li>
<li>Logged in cookie</li>
<li>Debugging option</li>
<li>console for precise manual purges</li>
</ul>
This plugin also auto purges Varnish Cache / Nginx Proxy Cache when your site is modified.
Varnish Caching sends a PURGE request to Varnish Cache / Nginx Proxy Cache when a page or post is modified. This occurs when editing, publishing, commenting or deleting an item, and when changing themes. 
Not all pages are purged every time, depending on your Varnish / Nginx Proxy Cache configuration. When a post, page, or custom post type is edited, or a new comment is added, only the following pages will purge:
<ul>
<li>The front page</li>
<li>The post/page edited</li>
<li>Any categories or tags associated with the page</li>
</ul>
<a href="https://www.varnish-cache.org/" rel="nofollow ugc">Varnish Cache</a> / <a href="https://www.nginx.com/blog/nginx-caching-guide/" rel="nofollow ugc">Nginx Proxy Cache</a> is a web application accelerator also known as a caching HTTP reverse proxy. You install it in front of any server that speaks HTTP and configure it to cache the contents. This plugin does not install Varnish/Nginx for you, nor does it configure Varnish/Nginx for WordPress. It’s expected you already did that on your own using the provided config files.
Inspired from the following :
<ul>
<li>https://wordpress.org/plugins/varnish-http-purge/</li>
<li>https://github.com/dreamhost/varnish-vcl-collection/</li>
</ul>

Varnish/Nginx Proxy Caching

Wordpress Varnish Cache 3.x/4.x/5.x and Nginx Proxy Cache integration

Oliver Whysall

Test your wordpress url to see if it contains the Varnish Cache HTTP headers using the API available at https://isvarnishworking.co.uk

Is Varnish Working?

Test your wordpress url to see if it contains the Varnish Cache HTTP headers

Varnish/Nginx Proxy Caching vs Is Varnish Working?