Desk research against primary sources, with the issuing authority linked where a page states an official fee, rule or deadline.
The 60+ country list changes over time and is not reciprocal in any obvious way — a passport can gain or lose visa-on-arrival eligibility without the traveller's home country changing anything on its side, which is exactly why checking GDRFA's own list matters more than asking someone who travelled last year. The 30-day or 90-day allowance also depends on nationality, so two travellers on the same flight can legally receive different lengths of stay.
If you are travelling on a passport not in the eligible group, applying through Emirates or flydubai as part of a booking is usually faster than going directly through a UAE sponsor, since the airline's visa service is built around processing volume rather than individual case review. Either way, apply with enough margin before the flight that a rejection or a request for more documents does not force you to rebook.