https://dev.office.com/sharepoint/docs/spfx/sharepoint-framework-overview
In this new Client Web Part model there would be no IFrames. It will be all cient side thing.
My question is, where would the server code reside which is needed to support this new client side web part. for e.g some server side custom json/xml is queried.
Will that code reside in provider hosted App for SharePoint ??