If you are using Greenhouse or Lever, the hired reason is indicated below:
Lever this will be Applications with "reject_reason":"Hired"
Greenhouse this will be Applications in "Hired" stage
Unfortunately most ATS's allow people to create their own stages and orders so we don't have a way of automatically determining if a candidate was hired. However, this is a common use case for our customers, so they generally do the following:
After a customer links their ATS via Merge, allow the initial sync to complete
Once the initial sync finishes, prompt the user with all the job stages in their system.
Maintain the mapping on your end.