It is like ACH, but it settles in seconds, rather than in hours.
The current "same day" ACH schedule is that payments that make into the day's batch must be received at the Fed by 4:45 p.m. ET, a target file distribution time of 5:30 p.m. ET, and a settlement time of 6:00 p.m. ET. It's all batch files.
Anything that re-bills periodically will remain on ACH. ACH handles requests to debit someone else's account with ACH, and they can undo that later. That runs on a 3-day cycle. FedNow has to be initiated from the money sender end.
