Money exchange in Bangkok?

I have not been to Bangkok but as a travel agent, the currency exchanges at the airport are usually open 24 hours (Europe and US). These days it is much simpler to find an ATM and withdraw cash that way, if you bank allows you to do it for a reasonable fee, since you would be paying a fee at the currency exchange anyway. Otherwise, the hotel front desk can do it but also for a fee, usually fairly high.