We have a solution with this structure.
We want to use a dns structured like this:
http://www.ourapp.com points to OurApp.Web
http://api.ourapp.com points to OurApp.Api
We want to host on AppHarbor.
How can we do this?
AppHarbor currently only supports deploying one application from any given repository. One option might be to fold the API into the web project. I did this for a non-web API WCF service here.
Another option is to maintain two AppHarbor applications, and use solution files named according to what application you want deployed for that application. That is, OurApp.Web.sln
contains the Web project and any supporting projects and, OurApp.Api.sln
references the API project and any supporting projects. Read more about AppHarbor solution file convention.
(disclaimer, I'm co-founder of AppHarbor)