Recently we've been using a script to pull down Custom Object data via REST API which has been working great.
However, the only downside of this solution is that we have to provide the script an input file of either Email Addresses or GUIDs. We've been achieving this by exporting a CSV from a Smart List of "Has CustomObject: True".
Ideally we'd prefer to skip/automate this step
Does anyone know of any method we could query a Custom Object to return the GUIDs of all of its members? Or query the lead database and return only those that have that specific Custom Object data? I had a look through http://developers.marketo.com/ but didn't spot anything.