<p>I am a PHP developer who is kind of in a pickle. I'm trying to locate and/or build an API capable of speaking to Hotmail, Yahoo and GMAIL in order to retrieve contact lists (with the user's consent, of course). The one I'm having the most trouble finding is a Hotmail API.</p>

<p>Where would I start to look as far as finding either a working, stable API or the steps I could take to developing one for hotmail? Is there one that covers all of these bases that I could implement? Any help would be greatly appreciated!</p>

<p>Thanks!</p>

<p>EDIT:
I did manage to get a few services up, however, I've been using Open Inviter for at least one client project, and it seems to perform well.</p>

Rapleaf might have something for you:
http://www.phpclasses.org/browse/package/4436.html
It appears that this service plays cat and mouse with some providers, as not all e-mail providers offer a stable API for communicating with their services.  (It would undermine their business model.)  So, if you use these and the e-mail provider breaks the chain somehow, you're broken until Rapleaf catches up.