A Wake Up Call Service for Your Own Phone
An alarm can be silenced without waking up. That is the whole problem, and it is why the wake-up call outlived the hotel it was invented in.
Why a call beats an alarm
Dismissing an alarm takes one thumb and no consciousness. Most habitual over-sleepers can do it in their sleep, and do. A phone call is different in a small but decisive way: it keeps ringing, it comes from outside the device's snooze logic, and answering it requires you to say something. Speaking is much harder to do unconscious than tapping.
Two different searches
If you are looking for a hotel wake-up call, the front desk still does that and it is free. This is the other thing: a scheduled call to your own phone, from your own account, whether or not you are in a hotel.
Setting one up
Pick a time, pick daily or one-off, write what the call should say. It rings your phone at that time in your timezone and speaks the message. Change or cancel it whenever. If you travel, the timezone follows the setting you chose rather than the device.
Who uses it
Shift workers whose start times move, people whose phones are on silent overnight for family reasons, anyone on a landline in a house without a smartphone, and a fair number of people who have simply lost the argument with the snooze button.
Cost
7 calls free with no card, so you can test whether it actually wakes you before paying anything. Then $7.50 a month covers a daily wake-up call with room to spare.