We currently don't have an alarm, however, it's something that is on our roadmap to build.
We'd love to hear, via in-app chat or email firstname.lastname@example.org, what your perfect alarm would do—including what you currently use and what would get you to replace it.
It's worth noting that it's unlikely that we'd do an alarm that wakes you up in a "lighter" sleep phase because:
There is no validated scientific evidence that any tracker/wearable can track your sleep depth/stages. The only proven device that can do this a Polysomnograph that can measure your brain activity.
There hasn't been any strong evidence that waking up in lighter stages will make you feel less groggy. You will always feel groggy after sleeping as your brain clears out the sleep chemical adenosine. Research has found that you can reduce the impact of morning grogginess by either exposing yourself to sunlight to help get your energy schedule (circadian rhythm) started and reduce your sleep debt.