title: What are the differences between Koa and Express 4.0?
body: <p>Koa and Express 4.0 are both fairly new, and from what I've read, Koa was made by the Express team.</p>
  
  <p>From what I understand, Koa requires features of node that are only available in 0.11 (the unstable branch) of node, and also uses generators. Express 4.0 seems to only be the next version of the Express framework.</p>
  
  <p>Are there any differences I am missing completely? Is it likely (based on what the Express team has publicly stated) that Koa and Express will merge at some point in the future?</p>
  
  <p>Thanks!</p>