How do you check that a payout matches what was actually owed?

When a paid API call settles, the payment side is easy to prove. There is a transaction, an amount, a sender and a receiver.

The harder part starts after that. If that call was supposed to be split between a few parties, or counted toward a recoupment balance, or paid out at a different rate because of where it came from, the settlement alone does not tell you whether the right people ended up with the right amounts. You need something on the other side to check against: a record of what was owed, computed from the agreement, that the actual payout can be compared to line by line.

We have been going back and forth on how strict that check should be. Exact match on amount and recipient per line, with any difference flagged? Or is a periodic reconciliation that catches drift in aggregate good enough for most teams?

If you run paid APIs or a marketplace with splits, how do you verify payouts against what was owed, and where has that check caught something the payment logs missed?