Press kit

Restful press kit

The facts, copy-ready descriptions, screenshots and the icon, plus a plain account of what the app actually measures, including the parts that do not flatter it.

Checked against the app’s source code on 11 September 2026; store facts such as name, price and ratings were checked against the App Store listing on 10 September 2026. If anything here is wrong, email knowhiz.us@gmail.com and we will correct it.

Email the developer View on the App Store

At a glance

Name on the App Store: Restful: Sleep Tracker & Sound
Developer and seller: Curastone CORP.
Price: USD 2.99, paid once. No subscription, no in-app purchase, no advertising.
Platforms: iPhone and iPad, iOS 13.0 or later. No Android version.
First released: 11 May 2026
Current version: 1.0.6, released 10 September 2026 (UTC)
Category: Health & Fitness
App languages: English, Simplified Chinese, Japanese, Korean
Ratings: None yet, in any App Store country (checked 10 September 2026).
App Store: apps.apple.com/app/id6762536221
Press contact: knowhiz.us@gmail.com

About Restful

Written to be copied as-is. Every claim in them is checked against the app.

Short description

Restful is an iPhone and iPad sleep app from Curastone CORP. It plays sleep sounds, including four nature recordings, four synthesized city ambiences and a ten-channel mixer, and has a nap timer and a fixed-time alarm. Overnight, it listens through the microphone and charts how loud the room was, on the phone itself; no audio is uploaded. It needs no watch or ring, but its chart shows a pattern of sound, not a measurement of sleep stages. Restful costs USD 2.99 once, with no subscription, in-app purchase or ads.

89 words

One sentence

Restful is a USD 2.99, no-subscription iPhone app that plays sleep sounds, wakes you with an alarm, and charts the sound of your night from the phone’s microphone instead of a wearable.

The question everyone asks

How does Restful know I’m asleep?

It doesn’t. Restful measures sound and gives the pattern sleep-stage names. This is the full answer we give anyone who asks.

Recording. While a sleep session runs, from the moment you start it until you end it, the app records the microphone in one-minute pieces. Naps are not recorded.
One number per minute. A library on the phone reduces each minute to a single, uncalibrated number for how much sound the microphone picked up. It does not pick out breathing, snoring, movement or speech. Steady sound such as a fan or rain weighs heavily, while a single loud second counts about as much as a minute of soft background noise. Every sound counts, including the app’s own sleep sounds.
Compared with the same night. When the session ends, the minute values are smoothed into one point per ten minutes and ranked against the rest of that night, not against any fixed standard.
Labels. The quietest points are labelled “deep”, the loudest “awake”, and the rest “light”. “Asleep” is the time not labelled awake. The score combines that mix with how long the session ran: the length part peaks at about eight hours, and sessions over about twelve hours score at least 70.
Times. “Sleep onset” and “wake-up time” are the moments you started and ended the session.

What that means

Every night has “deep” and “awake”: Because each night is scaled against itself, almost every journal contains some of each, however you slept.
It cannot tell if anyone is there: Nothing checks that a person is in the room, so a session left running in an empty bedroom would still produce a journal.
Stillness is not sleep: Lying awake and still looks the same as sleeping quietly, and is often labelled deep sleep. A steady fan or white-noise machine does not stop the app from finding “stages”.
Interruptions read as silence: If a phone call interrupts recording, each whole minute is filled in as silence. Longer interruptions show up as deep sleep and can push the rest of the night toward “awake”.
Session length moves the score: The score depends on how long the session ran about as much as on the sound pattern. Sessions longer than about twelve hours score at least 70.
No validation on record: The method was written in 2020–21 and tuned by hand. We have found no record of it being compared with a sleep study, a wearable or labelled recordings, and we make no accuracy claim for it.

Treat the chart as a record of when your room was quiet and when it was not. If you need to know your sleep stages, a sleep study or a validated wearable is built to estimate what Restful does not.

Privacy

What leaves the phone

What the current version (1.0.6) sends, when, and to whom, including one problem we have not fixed yet.

Never uploaded

Audio, the per-minute sound values, the chart and the journal. There are no accounts, and nothing in the current version uploads journals. Like other app data, journals are included in your own iCloud or computer backups if you use them.

Sent automatically to Sentry

When you open the app, or return to it after 30 seconds or more away, it sends Sentry, a third-party crash-reporting service, a session record with random identifiers and timestamps. Crash, error and hang reports also include the device model, iOS version, battery and charging state, recent app events, and an identifier derived from Apple’s identifier for vendor and the device model, which can stay the same if you reinstall. Like any server, Sentry receives the IP address a report is sent from. None of this includes audio or journal data, and there is no in-app setting to turn it off.

Sent only when you tap

Sharing a night summary through WeChat or the iOS share sheet, saving it to Photos, emailing us, or rating the app. The WeChat sharing library, closed-source code from Tencent, is loaded when the app opens; we have not audited its network behaviour.

Known problem: audio left on the phone

In every version up to and including 1.0.6, a bug leaves some raw audio in the app’s storage on the phone: the piece being recorded when a session ends, usually under a minute, and any minute the app could not analyse. These pieces add up night after night. They are never uploaded, but they can be included in your own iCloud or computer backups. We are fixing it in the next app update.

Assets

Screenshots and icon

Screenshots of version 1.0.6, captured in the iOS Simulator with sample data. The scores and durations were made up for the screenshots, not produced by the app’s analysis of a real night. Full-resolution PNG, 1320 × 2868.

WelcomeThe first onboarding screen.
Download PNG
JournalA night summary: score, session times, and the time labelled asleep and deep. The chart’s in-app subtitle, “Movement and depth through the night”, overstates it: the chart shows sound level only.
Download PNG
InsightsAverages over 7 days, 4 weeks, 120 days or all nights, shown after seven tracked nights.
Download PNG
SettingsAverages from tracked nights, and the sleep-sound timer.
Download PNG
Sleep soundsThe sound library: four nature recordings and four city ambiences.
Download PNG

Restful app icon: an orange clock on a dark pillow.

App icon, 1024 × 1024 PNG.

Download icon

You are welcome to use the icon and screenshots in coverage of Restful. Please do not alter the numbers shown in a screenshot. Apple, iPhone, iPad and App Store are trademarks of Apple Inc.

Contact

Questions, corrections, review codes

Email knowhiz.us@gmail.com. We answer technical questions about how the tracking works, including everything on this page.

Review codes are available on request. Tell us which country’s App Store you use, because a code only redeems in the store it was issued for. A code comes with no conditions: we do not ask for coverage or for a positive review.

Email the developer View on the App Store