Ok thank you.

Strange because in most client it seems that if the invoice is not payed then the zap appears as "on hold" until the settlement is done.
It's like their is a way to actually know that the payment actually got through  

 Right - like every zap to a zeuspay address  

 The clients are just waiting for the lnurl service to publish the zap receipt for the zap that was sent. I think most clients at least verify that the invoice in the receipt matches the invoice from the zap event. 

 Yep, that is how I understand it
So it seems there is actually a way to know precisely enough how many sats have been send through nostr 

 Not really. Cause anyone can publish zap receipts without zaps even being sent. That’s what @benthecarman was trying to explain. 

 Ok understood 

 I think the only way to estimate the number is to tally up the numbers from zap receipts published by trusted custodial lnurl services. 

 Blinded zaps for a more robust verification method? 🤔