Even the most watchful parent can’t watch their baby all the time. But it’s hard to help babies get the sleep that’s so critical to their development—and parents’ sanity—without knowing how they sleep. Enter Nanit Plus ($279, plus $100 for a stand and one year of personalized tips), which is one part baby monitor, enabling parents to watch a live feed of their child via an app, and one part sleep coach: it tracks key factors about a baby’s slumber—including her surrounding conditions, such as humidity levels—to offer parents data-backed tips on how to improve it. If a baby stays awake too long in her crib, for example, Nanit might suggest adjusting the temperature or darkening the room. And while that level of surveillance may seem creepy to some, co-founder Assaf Glazer likens his device to a trusted babysitter: “I sometimes imagine my mother sitting above the crib, 24/7—she gives me advice so I can make better decisions tomorrow.” Eventually, he hopes to use Nanit for early detection of conditions like autism and sleep apnea. —Eliza Berman