Question

I know I can detect if a function is being run by an admin using:

Mage::getSingleton('admin/session')->isLoggedIn();

But I’m not sure if there is a similar call to determine if the environment is an API call versus a web visit.

Answer 1

You could check if the Mage_Api_Model_Server singleton has been initialized:

$apiRunning = Mage::getSingleton('api/server')->getAdapter() != null;