Dan Collis-Puro

Need for Speed?
This plugin handles the wordpress/php side of a statically cached nginx-fronted wordpress (or wordpress mu) site. It makes WordPress emit an “X-Accel-Expires: 0” header when a user is logged in or has taken actions that should cause them to get a customized page on your frontend. This – along with the nginx configuration below – will ensure logged-in users aren’t impacted by your static nginx cache.
Why would you want to statically cache wordpress with <a href="http://www.nginx.org" rel="nofollow ugc">nginx?</a>
<ul>
<li>INSANE performance. Hardware that could generate 6 pages / second can now generate many thousands.</li>
<li>Low resource usage. Even on very busy servers, nginx uses only a handful of RAM.</li>
<li>Unobtrusiveness. You plop nginx in front of wordpress and that’s pretty much it. This plugin (and nginx) is all you need to make your site digg- and slashdot- proof.</li>
<li>Stability. Nginx is rock solid.</li>
<li>Faster is better. All the web gurus agree – visitors like faster sites, even when the differences are slight.</li>
<li>Do more with less. Using a frontend proxy lets you keep your heavy wordpress apaches lightly loaded, letting you handle more concurrent connections and use less RAM.</li>
</ul>
We’ve been using a caching nginx proxy at the fairly busy <a href="http://blogs.law.harvard.edu" rel="nofollow ugc">blogs.law.harvard.edu</a> since September, 2009. The results have been dramatic: we’ve halved the amount of RAM we need, doubled our outgoing network throughput (nginx is fast!) and have had essentially no significant load spikes.
Drawbacks
There are a few.
<ul>
<li>Plugins that rely on php code running on each page view won’t work properly. This is similar to wp-supercache or any of the other static caching plugins. Stats, image rotation, etc. You should implement these features via javascript or third-party services, depending. </li>
<li>You need to install and configure an nginx frontend proxy – but see the “installation” tab. It’s really not that hard.</li>
</ul>
Notes
<ul>
<li>It is completely harmless to install and activate this plugin before you’ve got the nginx side set up.</li>
<li>YOU MUST keep this plugin activated as long as you’ve got an nginx frontend proxy active – otherwise, you’ll end up caching too much of your site, and authenticated users won’t see customized pages.</li>
<li>This plugin helps speed up access for authenticated users mainly because it makes all other traffic a negligible resource drain. I suggest installing <a href="http://php.net/manual/en/book.apc.php" rel="nofollow ugc">apc</a> (or another opcode cache) and – alternatively – a wordpress object cache. Definitely install an opcode cache – leave the object cache for later. You may find you don’t need it!</li>
</ul>
<h3>The Future</h3>
This plugin could be set up to allow you to manage caching policies entirely from a wordpress control panel. We’d do this by manipulating the timeout in the “X-Accel-Expires” header based on the type of resource that’s been requested.
It’d be nice to de-cache when pages change via some call from the backend to the nginx frontend.

WordPress Nginx proxy cache integrator

Enables your blog to work properly with an nginx frontend static proxy cache. ASTRONOMICAL performance is yours!

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

WordPress Nginx proxy cache integrator vs Varnish/Nginx Proxy Caching