I have 3 application servers:

Whenever they start they schedule a repeatable job:
paymentsQueue.process(function(job){
// Check payments
});
// repeat payment job every 60 minute
paymentsQueue.add(paymentsData, {repeat: {cron: '0 * * * *'}});
Does it mean that payment will happed 3 times in 60 mins, or bull is smart enough to run it once on one of the servers?
It will run only once in one of the servers.
Most helpful comment
It will run only once in one of the servers.