How long is my bus ticket valid in the Netherlands?

Your bus ticket becomes valid 15 minutes before the departure of your booked bus ride. Therefore, the QR code appears in the app 15 minutes before your bus departs, and the ticket expires 30 minutes after your scheduled bus arrives. That means you can still board your bus up to 30 minutes after your bus was scheduled. So you can take a bus a little earlier or a little later. If you bought a 2-hour ticket(HTM/RET), then of course that ticket remains valid for 2 hours.

An Arriva bus ticket is valid 60 minutes before departure and remains valid until 4 hours after the scheduled departure time of the bus.