I posted my Canadian tax return a couple of days before the deadline, which was 2025-04-30. I have already received an acknowledgement: #RevenueCanada has processed my return and figured out that I overpaid them a bit. It will be deposited in my bank account in a few days.
I posted my US tax return a couple of days before the deadline, which was 2025-04-15. The #USIRS `where's my refund' online tool doesn't admit the return exists yet.
So much efficiency in the US government these days.