Simple paper ballots with scrutineers from both sides watching the count - and I’ve seen more than a few scrutineers pointing out mistakes that went against their side. They take great pride in ensuring the system is fair.
Fraud isn’t impossible - but it’s not going to be easy.
As it should be. Too bad we cannot report our votes from each congressional districts like this. It’s actually kind of fun to watch. However it would be difficult in Wyoming and Alaska which are huge single district states.