There isn't sufficient information about what is needed on the server side to host Open Social Apps. Open Social API documentation seems to mainly deal with the client side.

Am I right in assuming that on the server side I can implement any logic to retrieve user data; but as long as I expose standard URL endpoints (for ex: http://{domain}/feeds/people/ for People Data API) and return data in expected XML format, as described by the documentation, the server can interact successfully with the Open Social Gadgets?

Or is there more to it? And what is SPI?

Thanks