The use of temp files in FME is not uncommon and the process for creating temp files right now in the middle of a workflow seems more complicated than it needs to be. 

The current workflow requires a user to put down a TempPathNameCreator and each feature which goes through this will create a new pathname, this is rarely desired. You need to use a FeatureMerger or something similar to get the correct path onto all of the feature which over complicates the process. 

Better would be an option to either put the same path on each feature, or add a GroupBy. Even better still would be an option directly in the FeatureWriter/HTTPCaller to just output to a temp location and doing away with need for the transformer in many workflows.

An additional benefit of changing the way this works would also be in debugging. At present if you want to inspect the temp file in a workflow you either need to modify/disable parts of the workflow and/or change the path in the FeautreWriter/HTTPCaller. 

Furthermore, the TempPathnameCreator can also be a problem when working with partial runs, indeed, this probably won’t go away with adding the option to the FeatureWriter/HTTPCaller, however, it’s another issue which complicates the process.