It appears there are now two implementations of the AtomAPI. The first is blojsom:

So I decided that since the race today was rather boring, I would sit down and do an implementation of the EchoAPI editing api.[- Mark ]

The next is Danny Ayers who put together an implementation in a mornings work:

I was curious to see just how simple the Atom API actually was to use, and so have written a totally minimal blogging system using it - three files, a morning's work. All it does is post entries from a HTML form and add them to a file containing all the entries on the server side (as in section 5.2 in the API). The code's not for the purists, but it pretty much follows the spec and really is simple! [Danny Ayers]

Is it too early to start interoperability testing?

I have started a validation suite for Atom  called bikini.  You can see some of the initial docs at

Posted by Nick Chalko on 2003-08-05