Citrus Stack

Citrus stack is high performance web server environment based on fine tuned configuration of open source software. We have decided to give it special code name to distinguish it as high performance server stack for the modern web:

  • Latest Nginx. Support HTTP/2 connections in every version of Chrome browser. It is compiled with recent OpenSSL, making it more secure and bringing wider support for HTTP/2 to your users.
  • DKIM. Every email message your server sends is signed with DKIM key. What gives? Your website visitors and clients never have to hunt for your message in their junk mailbox
  • PHP Opcache. Your PHP scripts don’t need to be parsed all the time! We make it so there is no extra time spent on parsing the PHP scripts. This feature is very important to have with Wordpress, Magento and other large frameworks.
  • Google PageSpeed. What gives? Serve WebP optimised images to supporting browsers to speed things up further
  • Your website SSL will score A+ in Qualys SSL labs test
  • Linux network tweaks are applied at kernel level
  • Website security. Your website runs with proper security. Each website has its own dedicated site user to isolate sites from each other and secure better.
  • Varnish. We believe nothing is more important to performance than supporting high traffic. Do you want just to score in a PageSpeed test for nothing or you want more sales, more customers, faster speed? You  don’t want your website to die when it gets a few more visitors hitting the homepage? We’re on the same page now! Our optimised configuration for WordPress and Magento will take care of all that – support thousands of visitors, more sales, more income and more speed now
  • Nginx microcache. Want some more performance juice even with Varnish? This is the extra bit we have .
  • Redis. Stores PHP sessions in RAM
  • PHP-FPM 7 for unmatched PHP performance
  • Fail2ban will protect your system from brute force attacks
  • Nginx Amplify will monitor and troubleshoot Nginx configuration
  • Percona MySQL. It’s the same MySQL , optimised for performance by good guys from Percona
  • Postfix. Reliable mail delivery agent. Configured to send outgoing email only, making sure that your server will not get into block lists.

More features:

HTTP/2 support in Chrome.

We have prepared a special YUM repository with Nginx built against OpenSSL >= 1.0.2 in order to support ALPN protocol negotiation for HTTP/2. This is for our customers only.

Verify if your website support HTTP/2 in Chrome here.

Brotli compression.

Citrus has complete support for the brand new compression method by Google. The Brotli compressed files are served with maximum compression level 11 and don’t require much CPU thanks to special configuration ingredients. Shrink down that CSS or JS to 10KB from 100KB! For those interested to implement Brotli compression with Varnish on their own, checkout this post on enabling Brotli in Varnish.

Our special recipe Brotli configuration works even with PageSpeed module!


As good as always 🙂