The varnish docs have a couple of philosophical essays on why they don't support SSL:

https://www.varnish-cache.org/docs/trunk/phk/ssl.html

https://www.varnish-cache.org/docs/trunk/phk/ssl_again.html

I think they are well justified in enforcing the separation of SSL code from caching memory management.

And no support for HTTP/2 until recently. They're suggesting Hitch for SSL termination now.

[1]: https://info.varnish-software.com/blog/varnish-cache-5-http2...

Edit: Apache also has caching/does it all in one package; they're even contemplating a module for certbot (in addition to or as replacement for the official certbot/letsencrypt Python package for Apache)

Is nginx as a reverse proxy as efficient at caching as varnish? Asking as I haven't found any benchmarks on the subject.

I'm using varnish via Fastly, and have come to greatly appreciate the fast cache-clear, so we can push all content out into the cache, not just static assets.

I believe NGINX's caching is as efficient, if not moreso, but it is less flexible. The tools available to you in Varnish's VCL are substantial, plus you get ESI support - something NGINX lacks.

Also selective cache purging is a paid feature with nginx.

If you're using the filesystem backed cache with nginx, selective cache purge, stats, etc, is a fairly trivial scripting task.

Agreed, There is also an OS alternative which essentially mirrors the functionality of propriety nginx cache purge: https://github.com/FRiCKLE/ngx_cache_purge

Hence you can just build it with your standing nginx binary reducing the need for miscellaneous scripts.

thanks for the info/link!

I doubt there's a notable performance difference, and it's a bit of apples and oranges unless you front varnish with something that does SSL for your benchmark. Not many use cases for plain http caching anymore.

Varnish does likely have an edge with flexibility and expressiveness around configuration, since it's a single purpose tool.