Returns a single attachment resource by ID, including the file_size field.
Example response (abbreviated):
{ "data": { "type": "attachments", "id": "7", "attributes": { "id": 7, "post_id": 101, "original_filename": "screenshot.png", "mime_type": "image/png", "origin": "web", "file_size": 48291, "created": "2026-04-01T09:30:00+00:00", "created_by": 851, "created_by_info": { ... }, "enabled": 1 } }}HTTP codes:
Returns the attachment resource.
The API user is not an ATS manager, does not have visibility permission for this attachment, or the attachment does not exist.