title: Existing PHP Tool for Feature Toggle
body: <p>Recently I've read a number of articles talking about the idea of using "feature toggles" or "gatekeepers" to keep features hidden from users until the development is done. Facebook and Flickr both also talk about how they use this to test new features with a subset of users before unleashing them on everyone.</p>
  
  <p>A bit of googling didn't turn up any existing PHP packages/tools that can be added to a web app to handle this type of thing. It seems straight forward enough to roll our own but no reason to re-invent that wheel if we don't need to. Are there any existing PHP tools to do this?</p>
  
  <p><strong>Articles</strong></p>
  
  <ul>
  <li><a href="http://martinfowler.com/bliki/FeatureToggle.html" rel="nofollow noreferrer" title="Feature Toggle">Feature Toggle</a> by Martin Fowler</li>
  <li><a href="http://code.flickr.com/blog/2009/12/02/flipping-out/" rel="nofollow noreferrer" title="Flipping Out">Flipping Out</a> on Flickr DevBlog</li>
  </ul>
  
  <p>Clarification: The part of this that I'm looking to see if it exists is the admin panel that controls which users can see the new features. In Flickr's example, they can turn it on based on the host. In the Facebook example, they add functionality such as limiting a feature to 5% of users, only TechCrunch users or only East coast users.</p>
  
  <p>The admin panel seems crucial when you have 200 turned on features, 10 features that aren't quite done yet and 3 more that you're demoing for some users.</p>