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I began my test of the Snoo Smart Sleeper as a robotic-bassinet skeptic, certain that it couldn’t possibly justify its cult-like fandom in the parenting world. But this attitude didn’t last long. central patient monitoring system
From the day I put my baby into his first Snoo swaddle and clipped him in, the Snoo proved to be effective at keeping him asleep longer than any other bassinet in our testing lineup.
The Snoo is the brainchild of Dr. Harvey Karp, celebrity pediatrician and author of The Happiest Baby on the Block, which has been a parenting staple for two decades.
There are other “smart” bassinets out there. But when it comes to automatically rocking and shushing a fussy infant, the Snoo is in a class of its own.
Like many baby bassinets, the Snoo is intended to be used only for a few months. Babies outgrow it when they reach 25 pounds.
At $1,700 (when not on sale), the Snoo is among the most expensive bassinets you can buy. However, you can also rent it by the month or seek out a used one.
In the earliest days—when he was just 3 or 4 weeks old—my baby didn’t sleep through the night in the Snoo. He still woke up crying every two or three hours to eat, which is a normal pattern for that age. But I was able to put him back in the Snoo immediately after a feeding without having to spend 20 additional minutes rocking him to sleep in the glider. And this added up to a lot more sleep for my wife and me throughout the night.
As the weeks passed and my little guy adjusted to Snoo life, his wake-ups became less frequent, until I had to start setting an alarm to get him up for meals. (For the first few months of life, regardless of where they’re sleeping, infants need to eat every two to four hours.) At 5 weeks old, he would have happily slept through the night in the Snoo without my intervention.
When my family was testing 10 models for Wirecutter’s guide to the best bassinets, we found ourselves returning to the Snoo because it was so effective at helping our entire family get more hours of nightly sleep. But it doesn’t work for everyone, and some experts we interviewed voiced concerns about the Snoo.
Wirecutter staffers have been testing the high-end bassinet since 2018, with very mixed results. And as desperately as new parents crave sleep in those first exhausting months—for their babies and for themselves—many people also end up having concerns and complaints about the Snoo.
Here’s everything to consider before you buy (or rent) this pricey bassinet. To read about more options for your baby’s first bed, check out our guide to the best bassinets and bedside sleepers.
Outfitted with sensors, this electronic bassinet promises to detect a baby’s needs and soothe them to sleep with automated rocking and white noise.
If you’re reading this guide, you likely already know this high-end baby sleep machine by name. For the uninitiated: The Snoo is an electronic bassinet—intended for babies up to about 6 months old—that relies on a series of smart sensors to recognize when a restless infant needs comforting.
For its smart features to activate, the Snoo requires the use of proprietary Sleep Sack swaddles, which have wings that clip into the side of the bassinet, securing an infant in place. Three swaddles are included with the purchase of a Snoo. (The uncanny valley–ish doll used in the photo above is 18 inches long; the average length of a newborn is 18 to 22 inches.) When the Snoo detects a baby’s cry or wakefulness, it automatically starts rocking and shushing, and this increases in intensity until the baby is soothed—or not.
The Snoo was the brainchild of Dr. Harvey Karp, author of The Happiest Baby on the Block, with help from iconic Swiss designer Yves Béhar and a handful of MIT engineers. Upon its introduction, in late 2016, it was the subject of almost rapturous admiration. “Worth Every Penny!” read just one of the many grateful reviews online (that one was from a mom who claimed the Snoo helped her 7-week-old baby go from sleeping only 90 minutes at a time to passing out for 12 hours straight).
In its early days, the high-tech bassinet garnered attention from Wired, CNET, CNN Business, New York magazine, and Fast Company, which called the Snoo “the best crib most parents can only dream about.” The New York Times profiled Karp in 2018, in How Harvey Karp Turned Baby Sleep Into Big Business.
The Snoo is designed to do something that parents have been doing for as long as any of us can remember: rock and soothe babies back to sleep.
At first glance, the 38-pound Snoo looks like a regular, if especially stylish, bassinet. Hidden underneath the mattress pad, however, is a mess of hardware that, in the company’s words, makes it “the smartest, safest baby bed ever made.” (In March 2023, the Snoo Smart Sleeper was given De Novo approval by the FDA to market itself as an over-the-counter infant sleep system for its ability to keep sleeping infants on their backs.)
The genesis of Karp’s idea came during a lecture, in which he pointed out that the number of infant sleep deaths in the US had gone largely unchanged in 20 years. “Why don’t you do something about it?” an audience member yelled up at the celebrity pediatrician. Karp decided he would invent a bassinet that was designed to keep infants alive and parents sane.
The Snoo is a natural extension of Karp’s thesis, which is the bedrock of his bestseller: that newborns are essentially in a fourth trimester and need a lot of noise and movement, as well as the feeling provided by a tight swaddle, to engage what Karp calls a baby’s “calming reflex.” In essence, the Snoo is designed to do something that parents have been doing for as long as any of us can remember: rock and soothe babies back to sleep.
When we first considered the Snoo, back in 2017, it felt like a niche product whose price put it out of reach of most parents. But since then, the Snoo has gone more mainstream, and it’s become clear that plenty of people are willing to shell out whatever it takes for the promise of more hours of sleep. (The Snoo can often be found used, and it is also available to rent, which is a more affordable option for most people.)
Karp remains a tireless advocate for his invention. His company promises that the Snoo will lead a baby to sleep one to two hours more per night, as well as sleep-train them and ease the transition into a regular crib. (We’ve discovered that not all parents find those two things to be the case.)
There’s no doubt, though, that the Snoo secures a baby in a safe sleeping position—on a firm surface, on their back—ensuring that they will not roll over onto their stomach without a parent noticing. There’s also no question that sleep is important—both for babies and for the mental and physical health of their often-overwhelmed parents. Karp argues that using the Snoo can reduce postpartum depression and a slew of ill effects attributed to a lack of sleep, from car crashes to marital implosion. (He has expertly made the hard sell countless times, including on recent podcasts.)
The inconvenient reality is that all babies are different, and it’s impossible to know in advance whether the Snoo will work better for your family than a bassinet that costs, say, a tenth as much. As some first-time parents and Snoo owners who’ve used only the Snoo have wondered aloud, “Maybe it works? Or maybe our baby is a good sleeper?” Parents whose babies have disliked the Snoo at first but later seemed to grow accustomed to it—sleeping for stretches of three to four hours—may wonder the same thing. Was it because of the expensive technology? Or did the baby merely grow out of their initial fussiness?
Wirecutter first reviewed the Snoo (above, second from right) as part of an initial round of bassinet and bedside-sleeper testing conducted by writer Caleb Hannan in 2017. Since that original testing, the same Snoo bassinet has been passed among eight different Wirecutter parents. Some have adored it; others have been ready to kick it to the curb well before its six-month recommended-usage period was up.
I took over Wirecutter’s baby bassinets coverage in 2022, while pregnant with my second kiddo. With my first baby, I relied exclusively on the relatively utilitarian Arm’s Reach Clear-Vue Co-Sleeper Bassinet (pictured above, in the middle; we continue to recommend it in our guide to the best bassinets and bedside sleepers). When my son was born, in summer 2022, the Snoo was one of 10 bassinets my wife and I tested over those first few months.
Along the way I also studied the work of Snoo creator Harvey Karp, including his well-known newborn-sleep book The Happiest Baby on the Block. I spoke with several pediatric experts, including Rebecca F. Carlin, MD, of the Columbia University Department of Pediatrics, a pediatrician and one of the co-authors of the AAP’s 2022 safe sleep guidelines; Aleesha Burke, IBCLC, a lactation consultant (and Snoo skeptic) in Layton, Utah; and physical therapist Stacy Conder and occupational therapist Susan Klemm of Carolina Kinder Development, in Charlotte, North Carolina, who also advise against the use of Snoo and other smart bassinets.
And, of course, I relied on the advice of the key organizations that set US safety standards, including the Consumer Product Safety Commission (CPSC), the National Institute of Child Health and Human Development, and the AAP.
In earlier reporting on the Snoo and other baby bassinets, writer Caleb Hannan consulted with infant sleep experts including Dr. Karp; James McKenna, PhD, head of the Mother-Baby Behavioral Sleep Laboratory at Notre Dame; and pediatrician and author Bill Sears.
Want a bassinet with storage? A co-sleeper with a drop-down side? Automated rocking? Whatever your needs, here are six models worthy of being baby’s first bed.
At first glance, there’s nothing that reads particularly high-tech about the Snoo Smart Sleeper. It looks like a sleek and stylish bassinet, with white mesh walls anchored by a wooden base and chrome legs that give off a vaguely Scandinavian vibe.
But beneath that serene exterior, there’s a lot going on. The bassinet—which has to be plugged in to work and pairs with an app—is outfitted with a microphone and sensors that allow it to tell (via sound and motion clues) whether your baby is awake and in need of soothing. The bassinet responds accordingly with automated swaying and shushing, coaxing the baby to sleep and ultimately allowing parents to get more rest during the bleary, exhausted first months of newborn life.
When the Snoo is on and your baby is calm, it plays a quiet stream of white noise and gently sways the baby from side to side. If your baby fusses or cries, the level of swaying and shushing will gradually increase in intensity, moving up to the fourth and final level if the baby is not soothed by the milder settings. (You have the option to intervene and decrease the speed at any time during this process, if you think it’s too much.)
If the highest level doesn’t quiet and soothe your baby within a designated period of time, the Snoo stops moving entirely and notifies you via its app to attend to your baby. Basically, it’s tagging you as a parent to do a diaper check, get a bottle ready, or figure out whatever else it is that your baby needs.
The concept behind the Snoo is well established. Its designer, pediatrician Harvey Karp, popularized a method of calming babies, called the 5 S’s, in his best-selling book The Happiest Baby on the Block (published in 2002). Caregivers have long embraced and implemented the S’s (swaddling, shushing, swinging, sucking, and holding a baby in a side or stomach position). But the Snoo does a lot of that work for you, enabling an infant to sleep longer and more deeply with less parental intervention.
It’s not like humans are totally forgotten in the process: The Snoo’s features are designed to mimic the relaxing sounds and motions of the womb. The idea is that a baby feels comforted by the familiar during the so-called fourth trimester—a time when the outside world is an unfamiliar and unsettling place. That’s when it works as promised, of course.
The Snoo’s app is easy to use, and it lets you track your baby’s sleep patterns over time. You can also activate the Snoo’s sound and motion without Wi-Fi or the app, by pressing a button on the front of the bassinet that takes you through the various motion levels. Most people don’t do this because the app is so convenient. But if you have unreliable Wi-Fi, or you find yourself suddenly without it, the Snoo will still be functional. (You do, however, need to plug it into an electrical outlet.)
The decibel range of the bassinet’s white noise varies according to the different levels. The all-night baseline sound—which mimics the womb’s soothing rumble, according to a company spokesperson—comes in at 65 to 70 decibels, whereas Level Four, the highest level, is about 84 decibels. “That sound cannot last, [since the] Snoo automatically stops if a baby crying continues for more than 3 minutes,” the spokesperson told me.
For context: The sound of normal conversation is in the 60 decibel range. Prolonged exposure to noise over 70 decibels could have a cumulative effect. Speak to your pediatrician or health provider if you have concerns.
At 38 pounds, the Snoo is heavy to move, but it’s easy to assemble without tools—it took me only three minutes—and it has a compact footprint of 35¾ by 19 inches.
The bassinet comes with an organic cotton sheet and a starter pack of three Snoo Sleep Sacks—proprietary swaddles you zip your baby into and then hook onto two plastic clips affixed to the bassinet’s base. (The device doesn’t turn on unless the baby is securely fastened in; so if a baby doesn’t like being swaddled, the Snoo’s features aren’t of any use.) By attaching the swaddle to the mattress clips, you are effectively immobilizing your child on their back within the bassinet.
The cover of the mattress is water-resistant, and the mattress and mesh can be spot-cleaned with a mild soap or detergent. Unlike some of the other baby bassinets we recommend in our guide to the best bassinets and bedside sleepers, the Snoo has no built-in storage.
The company recommends the Snoo be used until a baby is 6 months old, until they can get up on their hands and knees, or until they hit the Snoo’s 25-pound weight limit—whatever comes first (most babies still weigh less than 25 pounds at 6 months).
When considering a Snoo, you should also factor in the cost of purchasing additional Snoo Sleep Sacks (which come in different sizes), if you want to have extras. We’ve found that it’s usually possible to find them for much cheaper—both new and used—in online marketplace sites than it is to purchase them directly from Happiest Baby.
A newly purchased Snoo comes with a limited one-year warranty, which applies only to the original buyer.
Since 2017, eight Wirecutter staffers and contributors have used (with their newborns) the same Snoo bassinet we used for our original testing (above is baby number one, who kindly cooperated with our photographer even though she was not a Snoo fan). Another half-dozen Wirecutter parents have bought and used the Snoo on their own.
Of this sample, a clear majority liked the Snoo and said they would recommend it to a new-parent friend, and several people said they actively loved it. But three parents intensely disliked the Snoo—one said it brought to mind a “medieval torture device.” And some other parents were neutral on it, left unsure whether it was clearly superior to other (much simpler and less expensive) baby sleep options.
Some parents reported that the Snoo simply didn’t work for them—their babies just didn’t like it, or they found it was too much trouble to deal with, given the number of feedings and diaper changes that are required early on. Others found that once a baby was accustomed to the Snoo (which is not easy to travel with), it was difficult to travel or visit family.
Others struggled with weaning their babies from the Snoo and moving them to a traditional crib after four to six months. (The Snoo does have a “weaning mode,” which is meant to be used at around the five-month mark to prepare for the transition to a Snoo-less life. In weaning mode, the white noise continues, but there’s no motion. If the baby starts to fuss, the Snoo will increase its shushing and activate its soothing motion for a few minutes, just until the baby settles down.)
A Wirecutter editor who used the Snoo for her baby with some success noted (as some Amazon reviewers have) that she especially liked how the integrated swaddle kept her daughter sleeping on her back. Like some other owners, however, she found that the noise and motion response sometimes didn’t actually soothe her daughter. And once her daughter started experimenting with and making more sounds, the Snoo would mistake them for cries and respond with what felt like overzealous rocking. Once that happened, the editor tended to leave the Snoo off and use it as a regular bassinet. (A small laboratory study published in PLOS One investigated several metrics associated with infants’ calming responses. It found that the swaddling, sound, and movement of a smart crib and parental soothing were both effective for reducing fussiness.)
When Caleb Hannan, the original author of our bassinets guide, found that his baby did not appreciate the Snoo, Karp offered to give Hannan and his wife some personal counseling sessions. (Every Snoo comes with the promise of robust, 24/7 customer support, though clearly our writer got the VIP treatment.)
Some of Karp’s recommendations for Hannan’s daughter (who appeared to hate the very idea of lying flat on her back) seemed laughably low-tech for such a pricey product, according to Hannan. Karp suggested that Hannan put two cans of tuna underneath the legs of the Snoo, to elevate his daughter’s legs. He recommended zipping up a pound of rice in her swaddle to give her the feeling of having slight pressure on her chest. And he suggested that Hannan roll up a blanket beneath his daughter’s legs to help her get gas out.
Hannan said that Karp knew the suggestions he was offering sounded silly, but he said Karp seemed sincere in making them strictly for the benefit of the baby’s sleep. Even with all of Karp’s suggestions, though, Hannan’s daughter resisted the many charms of the Snoo. Like a lot of infants, she simply refused to sleep much, or at all, for the first six weeks of her life. The only times she seemed to be satisfied, Hannan recalled, were when she was lying sideways on his wife or on him.
I interviewed multiple experts who were in favor of the Snoo, but I also spoke with experts who voiced concerns. Among the issues? The Snoo can work so well that babies may not wake up on their own to eat (as I myself experienced). If parents aren’t diligent about setting alarms every two to four hours for feedings, babies could potentially end up suffering from “failure to thrive.” This is the term for when a child’s weight or growth rate falls significantly below that of their peers, cautions Aleesha Burke, a lactation consultant in Layton, Utah.
Other experts also advise against using the Snoo, including Stacy Conder, a physical therapist, and Susan Klemm, an occupational therapist—both of the Carolina Kinder Development pediatric practice in Charlotte, North Carolina. Because Snoo babies aren’t repositioned often enough, they say this could potentially exacerbate head and neck conditions such as plagiocephaly (back-of-the-head flatness), torticollis, and brachycephaly.
And since the Snoo swaddle pins the baby to the bassinet surface, it keeps the baby from practicing developmental skills, like rolling over, as they grow. A pediatrician I spoke with didn’t name the Snoo specifically but suggested that a smart sleeper that uses prolonged swaddling could hamper gross motor development, by preventing a baby from trying to roll in the 2- to 4-month window. The Snoo’s maker says it can be used for babies up to 6 months old, but that’s a long time to go without the freedom to roll over, considering how many hours infants log in their beds.
As of early 2024, the Snoo is $1,695 purchased at full price directly from the Happiest Baby site (though it does go on sale); it’s also available through Amazon and other retailers. It can also be rented directly from Happiest Baby, for $159 per month for the first four months (plus a $100 “cleaning and reconditioning” fee and a $99 refundable security deposit).
If you’re unsure about the Snoo, renting could be a good, lower-risk option. And even if you are very sure the Snoo is for you, renting is ultimately less expensive if you intend to use it only with one baby and/or you don’t want to go to the hassle of trying to sell a used bassinet.
When you buy the Snoo, it comes with three Snoo Sleep Sacks in three different sizes (small, medium, and large) for use as your baby grows. If you rent the Snoo, you’ll get just two Sleep Sacks (one small and one medium). Those are yours to keep.
The price of the Snoo can work out to the cost of a daily latte. If you actually find that the Snoo is the only thing that helps your baby sleep, this could feel like a bargain. Of course, the value is better if you use the Snoo for the full six months, and—if you buy it outright—you use it with multiple children or sell it once your baby is done using it. It’s not uncommon to see parents online renting out the Snoo in the time between when their first child is done with it and their second child is born (or even conceived).
Snoo allows customers who buy the Snoo to return the sleeper a refund within a 30-day window (minus restocking and shipping fees).
If you rent the Snoo, you can schedule delivery based on your due date. Initial shipping is free—except to Alaska and Hawaii—but you do have to pay $60 for return shipping ($216 for Alaska and Hawaii).
The Snoo is known for having a healthy resale market, so you’re likely to be able to recoup a good portion of your initial investment if you do buy one. It’s not uncommon to see Snoos selling for about half the full price on Facebook moms groups or other online marketplaces.
In early 2024 we scanned the used-Snoo universe, finding that Los Angeles appears to have a notably competitive market for used Snoos. We spotted many for sale there, for under $700. In northern New England, around $800 was more typical. About $700 seemed average in the New York area, as well as in the Southeast. Newer bassinets with more add-ons, like new or lightly used swaddles, fetch a higher price.
Unlike any other baby bassinet we’re aware of, the Snoo comes with proprietary Sleep Sacks (one each in small, medium, and large), which have small “wings” on both sides. The swaddle’s basic design, with its interior Velcro panels and exterior pouch, is the same as that of Wirecutter’s swaddle pick, the Sleepea, and this one is made by the same company. But the wings allow the Sleep Sack to slide into safety clips on either side of the Snoo’s mattress, to ensure your baby can’t roll over. You cannot pair the regular Sleepea swaddles with the Snoo.
You can buy additional individual swaddles directly from Happiest Baby (for about $30 to $35 each), a three-pack of the same swaddles in the three different sizes, or shop for new or used ones on secondhand marketplaces.
The Snoo comes with a single fitted sheet. Additional ones cost about $20 (when not on sale) and are available in several colors and patterns. The sheets are also available in a three-pack.
If you want to elevate the side of the crib your baby’s head falls on (for example, if your doctor recommends doing so due to a cold or stuffiness), you can purchase two slip-on Leg Lifters for about $20 (when not on sale). Those risers can be used either with the standard legs or with the alternative Low Legs (which you can purchase if you want your Snoo to sit lower beside your own bed; these are about $65 when not on sale). We did not test either of these add-on leg options.
Happiest Baby also sells a Mosquito Net and a cloud-themed Sky Mobile, both of which are custom-made for the Snoo.
As we explain in our guide to the best co-sleepers and bassinets, the Snoo now has competitors. We’ve researched the field, and we tested the Snoo and two other automated bassinets side by side. And we think that if you’re convinced the Snoo is what you want, the competition is likely to disappoint. The fact is that the Snoo does more than its robotic competitors.
But if you think something more low-tech—but still tech-reliant—would meet your needs, we liked the 4Moms MamaRoo Sleep Bassinet enough to make it a pick in our guide. This bassinet provides automated rocking and shushing like the Snoo does. But with the MamaRoo bassinet, parents have to turn those motions on and off (either directly on the bassinet or through an app), instead of relying on the bassinet to sense what a baby needs.
Though the Cradlewise fell short of pick status, we also liked its features. (The Cradlewise is a Snoo competitor; it matches the Snoo’s price but has the added advantage of converting to a crib that can be used into toddlerhood.)
You can read more about both of these Snoo alternatives in our guide to the best bassinets and bedside sleepers.
Caleb Hannan contributed reporting in 2017 and 2018.
This article was edited by Kalee Thompson.
Caitlin Giddings is a freelance writer based in Austin, Texas. Her work has appeared in Bicycling, Runner’s World, Lonely Planet, Outside magazine, and more.
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