I forget how long it's been (decade? probably less), but I've been using an alarm app called Sleep Cycle. The premise is simple but effective -- it senses whet

I forget how long it's been (decade? probably less), but I've been using an alarm app called Sleep Cycle. The premise is simple but effective -- it senses whether you're in deep or shallow sleep, and rings the alarm within a 30 minute window before your set wake-up time. First few times I used it, it blew my mind. Effectively, it nudges you awake when you're almost awake anyway. It's so gentle. I'll never go back to a hard-set alarm clock.