Hi Jason.
The file url can be created next:
prehttps://api.appery.io/rest/1/db/files/data_base_id/file_name/pre
For example:
prehttps://api.appery.io/rest/1/db/files/33fd3d06e4b0a25c11c89917/2203612d-4134-4b16-8caa-716e7beddc09.1.png/pre
33fd3d06e4b0a25c11c89917 - is database id.
2203612d-4134-4b16-8caa-716e7beddc09.1.png - file name for "_files" collection.