sleep² sleeptracker & analysis User Reviews

Customer Experience

Positive experience55.8% of reviews
Neutral7.7% of reviews
Negative experience36.5% of reviews

~ Based on 52 written reviews from the US App Store.

Is sleep² sleeptracker & analysis Safe?

sleep² sleeptracker & analysis has mixed safety signals based on user ratings. AppsHunter Safety Score for sleep² sleeptracker & analysis is 69/100.

This assessment is based on 34 user ratings, with an App Store average of 3.4/5.

Safety Analysis

52.9% of ratings point to a safe experience
8.8% of ratings suggest some concerns
38.2% of ratings point to a risky experience

~ Based on 34 App Store ratings for sleep² sleeptracker & analysis.

Is sleep² sleeptracker & analysis Legit?

sleep² sleeptracker & analysis appears legitimate, with a few gaps. AppsHunter Legitimacy Score for sleep² sleeptracker & analysis is 68/100.

Based on 68 of 100 points across 7 verification signals from App Store and developer data.

Top reviews

Worth The Price

I used both free version and Paid version
I would absolutely recommend the app because the Data presentation and The accuracy of the metrics is extremely good and It actually helped me become better at my sleep anxiety and sleep apnea
The support is actually very good and they are easy to contact if you have any query or any question regarding the app
I would absolutely recommend this app
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Will Not Connect

Trying to connect with the Polar H10 is impossible even though my phone is connected and other apps don’t have issues connecting. Waste of time!

Response from developer

We’re very sorry for the frustration - this is definitely not the experience we want you to have. With the Polar H10, it is important that the sensor is not already paired or actively used by another app, as this can block sleep² from accessing it! Please try the following sequence: 1.) Ppen Polar Flow once, check for firmware updates and reset the sensor to factory settings. 2.) Then fully close Polar Flow and any other apps that may use the sensor. 3.) disconnect/forget the H10 in your phone’s Bluetooth settings 4.) After that, please connect the H10 only directly inside the sleep² app (not through Bluetooth settings first). If it still does not work, please contact us at hello@sleep2.com. We’ll gladly help you personally and hopefully change your impression of the app.

Connection issues

Could be a good app but I wouldn’t know. Connects to my polar H10 at night and I start sleep then when I wake up it can’t end my sleep or connect to my strap. Makes you delete the data.

Response from developer

Hello Pat9710! We’re very sorry for the frustration-especially when the recording starts correctly at night but cannot be completed in the morning. With the Polar H10, this can sometimes happen if the chest strap shifts during sleep or loses skin contact, resulting in insufficient signal quality for a reliable analysis. Does this happen every night or only occasionally? And do you see a specific error message when trying to end the recording or read out the data? Please contact us at hello@sleep2.com with these details. We’d really like to review your case individually and find a practical solution for you! If we can get this working reliably, we’d of course be very happy if your impression and your rating changes accordingly.

Accurate stats

Sleep stats

Response from developer

Hi JohnJohn! Thanks so much for your trust in our measurement accuracy – we really appreciate it! 😊 We're continuously working on refining the user experience and your feedback is very valuable in that process. If you’d like to share specific suggestions, feel free to reach out to us at hello@sleep2.com .... we’d love to hear from you!

Sleep scientists, not software developers

The app keeps surprising me with new bugs every day - losing my sleep data, not working well offline and a clumsy data entry UX. The sleep science might be solid but the app development skills are lacking. Hard to justify $20 per month for such a frustrating experience

Bugs

Constantly losing sleep sessions

Response from developer

Sorry to hear that, Villy_vonka! Losing sleep sessions is frustrating – but in most cases, there's a simple solution (e.g. the sensor is still connected to another app like Polar Flow). Just reach out to us at hello@sleep2.com – we’ll help you get it working smoothly again. Maybe you'll feel differently about the app once it’s all running properly?

Sehr hilfreich

Ich verwende seit einigen wochen sleep2 im intensive programm mit einem polar sensor und bin echt positiv überrascht. Jeden morgen bekommt man personalisiertes feedback mit verbesserungsvorschlägen für die nächste nacht und verschiedene übungen und lerneinheiten werden freigeschalten. Kann ich nur empfehlen!
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Incredibly pricey

Can you guys actually make it affordable lol. 15$ a month is crazy

App Crashed and No Data

After spending $500 on two H10 straps, you wake up to a closed app with no data. There is no way to recover your data in the app. Closing the app, repairing the sensor, and following the support documentation all failed. I should have checked the reviews before purchasing.

Very Accurate sleep data !

Connected with the polar h10 this is the best app for sleep tracking.

Response from developer

Thank you so much for your great feedback:) We are happy that you like the app & appreciate the precise sleep tracking with H10!

eingeschränkte track möglichkeit

Es sollte die Möglichkeit geben seinen Mittagsschlaf auch richtig zu tracken

Response from developer

Vielen Dank für die positive Bewertung und dein wertvolles Feedback! Wir freuen uns, dass dir die App gefällt und werden deinen Wunsch - den Mittagsschlaf zu tracken - bei zukünftigen Entwicklungen beachten!

Falsely Advertised

Paid for the PRO subscription, but it didn’t contain all of the metrics described. Additionally, the UI is quite poor for comparing data between nights and zooming into specific nightly data. And the final nail in the coffin resulting in cancelling subscription in under a week is no error detection or restart capabilities. I had nights where the device I wore (Polar H10) had a brief (5 second) Bluetooth signal loss, due to rolling onto my stomach while asleep. This resulted in Sleep2 ceasing all recording activity and dumping the ENTIRE night’s data.
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Response from developer

Thank you for your detailed feedback - we’re sorry to hear about your experience. Regarding the metrics, we’d really like to better understand what exactly was missing or unclear in your case. Please feel free to contact us at hello@sleep2.com so we can review this with you in detail. Concerning the recording: our algorithm requires sufficient data quality. If more than ~20% of the signal is affected (e.g., due to loss of skin contact or signal interruptions), we cannot provide a reliable analysis - in such cases, the recording may be discarded to avoid misleading results. We appreciate your feedback and are continuously working on improvements.

Good But Needs Improvement

This app, when paired with the Polar Verity Sense or Polar H10, provides what may be the most accurate consumer sleep tracking available. According to The Quantified Scientist on YouTube, the data quality is among the best — and from my experience, I trust the metrics it provides.

That said, the app experience itself holds it back.

First, as others have mentioned, the app occasionally freezes or fails to process the night’s recording — resulting in a complete loss of data. I’ve tried returning to the app multiple times over the past year hoping this issue had been resolved, but it still occurs. Losing an entire night of data is frustrating, especially when accuracy is the main reason for using it.

Second, the interface feels dated. It’s functional, but visually it looks retro — almost like something from the 1970s. A modern redesign would go a long way in improving the overall experience.

Third, the subscription price (around $19.99/month) feels steep given the stability issues. For an app at this price point, seamless data transfer and reliability should be expected.

Finally, it would be extremely helpful to allow multiple sleep sessions per calendar day. For those of us with fragmented sleep or irregular schedules, the current limitation makes tracking less practical.

In short, the sensor + app combination offers superior data compared to most other trackers. However, without consistent reliability and smoother usability, it’s fair to question whether it justifies the monthly subscription cost.
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Response from developer

Thank you for your detailed and thoughtful feedback! We truly appreciate both your positive remarks on accuracy and your critical points! We’re glad to hear that you value the data quality - that’s exactly where sleep² aims to stand out, especially with Polar sensors. At the same time, we fully understand how frustrating it is to lose a full night of data. In many cases, this is related to firmware versions, connection interruptions or parallel connections (with other apps or bluetooth settings). Your feedback on the UI, pricing and multi-session tracking is very valuable- we will consider your points in future updates! Please reach out to us at hello@sleep2.com - we’d really like to review your case in detail and see if we can find a suitable solution for you!

Great insight

Everything works well. Heart rate tracking is clearly the best. Sense I’m using the polar h10. I don’t have a way to test the accuracy. However it does seem to be more accurate than my Apple Watch SE 2nd gen.

Response from developer

Hi MerlinMetals, thank you very much for your positive feedback:) We’re happy to hear that everything works well for you and that you’re satisfied with the sleep tracking using the Polar H10. The Polar H10 provides high-quality raw data, which allows our algorithm to perform a much more precise sleep stage analysis than many consumer wearables. This is exactly why the combination works so well! We truly appreciate your trust in sleep² and wish you continued valuable insights into your sleep.

Very expensive and terrible with connecting to H10 Polar strap

It always gives me problems when connecting to the polar H 10 strap. The stress of always trying the different ways of resetting and repairing probably throws off the HRV readings anyway.

And it’s extremely overpriced. You probably would have a lot more people willing to pay if you lowered the price. Your profit would increase by more customers. I would expect seamless connections with my Bluetooth device as well.
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Response from developer

Thank you for your feedback. You’re absolutely right - after a recent update, the former “More” section was renamed, and all related settings can now be found under “Profile”, including the Apple Health integration. We’re updating the FAQ accordingly to avoid further confusion. The basic version is available free of charge, while the added value lies in the paid version, which reflects the continuous development and scientific validation of our algorithms as well as the ongoing improvement of the app. If you have any questions, please feel free to contact us anytime at hello@sleep2.com - we’re always happy to help and clarify things directly.

Very expensive and needs some updating

The instructions about exporting data to Apple Health is outdated (there is no “more” section for this as stated in the FAQ). I think
In general the permissions are now different for Health integration.

And it’s extremely overpriced

Response from developer

Thank you for your feedback. You’re absolutely right - after a recent update, the former “More” section was renamed, and all related settings can now be found under “Profile”, including the Apple Health integration. We’re updating the FAQ accordingly to avoid further confusion. The basic version is available free of charge, while the added value lies in the paid version, which reflects the continuous development and scientific validation of our algorithms as well as the ongoing improvement of the app. If you have any questions, please feel free to contact us anytime at hello@sleep2.com - we’re always happy to help and clarify things directly.

Meine neue Lieblingsbeschäftigung

Ich nutze den Schlaftracker erst seit 2 Tagen. Ich bin ganz begeistert und mag ihn sehr. Er hilft mir, auf einen gesunden Lebensstil zu achten und die Übungen in Form von Audios, Video und Schlafcoach sind auch sehr interessant. Im Tagebuch kann man 300 Zeichen verwenden. Ich kann dort viel lesen und bekomme Tipps und kann zwischen zwei Programmen wechseln, mein Medizinprodukt basiert auf wissenschaftlichen Studien. Und ich kann Sleep2 kostenlos dank der TK für 12 Monate nutzen. Ich finde Sleep2 ganz toll.
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Response from developer

Hi LeoMaximilianNu - Vielen Dank für deine großartige Bewertung:) Wir wissen deine Rückmeldung sehr zu schätzen und freuen uns, wie begeistert du nach den ersten Tagen von sleep² bist! Besonders schön ist, dass dir sowohl die hochpräzise Schlafanalyse (Pro) als auch das Schlaftraining (Intensiv) einen echten Mehrwert bieten und du unseren wissenschaftlichen Hintergrund zu schätzen weißt! Super, dass du über die TK zwölf Monate lang kostenlos Zugang sleep² erhältst, freut uns ebenfalls. Wir wünschen dir weiterhin viele positive Erfahrungen auf deinem Weg zu einem gesunden und erholsamen Schlaf:) Wenn du mal Fragen hast oder Hilfe benötigst, melde dich gern jederzeit unter hello@sleep2.com bei uns

Overrated

The highest subscription, Pro, doesn’t provide enough sleep metrics. Compared to the free Coros app for Coros devices, Sleep2 is less user-friendly, easier to navigate, and less scientific. It lacks features like light sleep cycle duration. HRV data is not graphed, but heart rate can be graphed second by second. If a Coros app with an optical sensor watch can show an HRV graph, a scientific app developed by professors should do the same. The main reason for an ECG heart rate sensor is for many HRV data points. The Kubios HRV app for iPhone can show a second by second graph while taking a measurement and it doesn’t have paywalls, pretty deplorable for Nukkuaa that this is app exists.
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Room for improvement

When it works it works well but the app itself is pretty buggy. It is prone to getting hung perpetually on loading screens then dropping your data for the night when you try to reopen the app which is incredibly frustrating. Wish they would focus on a higher quality of code.

Response from developer

Thank you for your honest feedback! We're really sorry to hear about the issues you've experienced. We're continuously working to improve performance and your input helps us prioritize. If you're open to it, we'd love to better understand what happened and assist you directly – feel free to reach out at hello@sleep2.com :) Hopefully, we can turn your experience around.

Lots of potential

I do believe their measurement accuracy - I just wish the offline UX was more refines

Response from developer

Hi JohnJohn! Thanks so much for your trust in our measurement accuracy – we really appreciate it! 😊 We're continuously working on refining the user experience and your feedback is very valuable in that process. If you’d like to share specific suggestions, feel free to reach out to us at hello@sleep2.com .... we’d love to hear from you!