Comparison

Sleep When I Sleep vs CerePlay

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

Sleep When I Sleep

This app alerts you when you're falling asleep while listening to audiobooks or podcasts. It pauses playback to help you easily find your place again. It utilizes Apple Watch health data to detect sleep and offers a reset function for continued use.

Highlights
  • Sleep detection alerts
  • Automatic audio playback pause
  • Apple Watch integration
  • Adjustable sensitivity
  • Easy start/stop functionality
Read full description

Audiobook & podcast users know that it is almost impossible to find your place once you have fallen asleep and play has continued. SWIS – Sleep when I sleep. Here is what you will love about SWIS for iOS: It is so easy to use. SWIS alerts you that you are falling asleep & if not dismissed will pause audio playback making it easier to find where you left off in a story or podcast. SWIS detects that you are falling asleep & sends you an alert through the watch. We recommend that you stop audio playback when alerted. However, should you feel that you are not falling asleep and dismiss it the App will reset at a less sensitive level and alert you should it again detect sleep. SWIS uses health data from your Apple Watch to determine that you are falling asleep. For accuracy, this data updates throughout the day. Simply open SWIS on your watch when you are listening to audio and press Start. When alerted or when finished press Stop. Apple Watch required. DO NOT RELY ON SWIS TO ALERT YOU THAT YOU MAY BE FALLING ASLEEP WHEN DRIVING. Apple standard Terms of use apply and can be found at https://www.apple.com/legal/internet-services/itunes/dev/stdeula/

About

CerePlay

Explore a wide range of text-to-speech voices in various languages and accents. Preview and purchase high-quality, human-like voices to enhance your device's linguistic capabilities for productivity or enjoyment.

Highlights
  • Browse text-to-speech voices
  • Multiple languages and accents
  • Preview voices before purchase
  • Human-like voice quality
  • Supports iPhone and iPad
Features
Read full description

Step into a world of voice diversity with CereProc's innovative app for iPhone & iPad. Whether you're enhancing productivity or simply indulging in the joy of listening, our app offers a seamless browsing experience of text-to-speech voices in a multitude of languages and accents. Preview voices before purchase to ensure they match your expectations and needs perfectly. Embrace the future of voice technology with the introduction of CereProc Version 7 voices, presenting CereWave alternatives that deliver remarkably human-like outputs. Transform your device into a powerhouse of linguistic versatility with CereProc.

Screenshots

Sleep When I Sleep3 screens
CerePlay4 screens

Verdict

The call

The clearest difference is review sentiment: CerePlay at 57% against Sleep When I Sleep's 0%. CerePlay also leads on rating (3.8 vs 1.0) and update cadence (every 3 weeks vs every 4 months). Sleep When I Sleep's advantage is iOS requirement (11.1 vs 17.2). On price, ratings volume, ads and in-app purchases there is nothing between them.

Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS

CostPrice · In-app purchases · Ads · Monetization

Both are free to download. Sleep When I Sleep sells 1 in-app purchase, starting at $5.49 per year and CerePlay sells 34 one-off in-app purchases. Whichever you choose, the download price is not the number that matters.

ReceptionRating · Positive reviews · Number of ratings

CerePlay holds the better App Store score, 3.8 against 1.0. Both are backed by a comparable volume of ratings — 2 and 4 respectively. Written reviews point the same way: 0% of Sleep When I Sleep's written reviews are positive against 57% of CerePlay's.

UpkeepUpdate frequency

Sleep When I Sleep ships an update every 4 months, CerePlay every 3 weeks. The most recent releases landed on October 6, 2026 and October 21, 2026 respectively.

Scorecard4 real differences · 6 level
Sleep When I Sleep versus CerePlay: the parameters behind the verdict, then further details
ParameterSleep When I SleepCerePlay
PriceFreeFree
Rating1.0 (2 ratings)3.8 (4 ratings) — better
Positive reviews0.0% of reviews57.1% of reviews — better
Number of ratings24 — better
Update frequencyEvery 4 monthsEvery 3 weeks — better
AdsNoNo
In-app purchasesYesYes
MonetizationFree with in-app purchasesFree with in-app purchases
DevicesiPhone, iPod, Apple Watch — betteriPhone, iPad
Requires iOS11.1 — better17.2
Further details — not scored
Size35 MB90 MB
Age rating4+4+
DeveloperSWIS APP LTDCereProc Ltd

Customer experience

Sleep When I Sleep

All ratings2 ratings
Positive0.0%
Neutral0.0%
Negative100.0%
Written reviews5 reviews
Positive0.0%
Neutral0.0%
Negative100.0%

CerePlay

All ratings4 ratings
Positive75.0%
Neutral0.0%
Negative25.0%
Written reviews7 reviews
Positive57.1%
Neutral0.0%
Negative42.9%

In-app purchases

1 purchases

Sleep When I Sleep

Subscriptions1
  • 7 Day Free Trial7 Days trial$5.491 Year
34 purchases

CerePlay

One-time34
  • Caitlin TTS$0.99
  • Carolyn TTS$0.99
  • Giles TTS$0.99
Show 31 more
  • Jess TTS$0.99
  • Hannah TTS$0.99
  • Katherine TTS$0.99
  • Isabella TTS$0.99
  • Kirsty TTS$0.99
  • Lauren TTS$0.99
  • Megan TTS$0.99
  • Sarah TTS$0.99
  • William TTS$0.99
  • Stuart TTS$0.99
  • Robot TTS$0.99
  • Sue TTS$0.99
  • Ylva TTS$0.99
  • Yuki TTS$0.99
  • Suzanne TTS$0.99
  • Adam TTS$0.99
  • Ben TTS$0.99
  • Daria TTS$0.99
  • Jack TTS$0.99
  • Mairi TTS$0.99
  • Ghost TTS$0.99
  • Demon TTS$0.99
  • Nicole TTS$0.99
  • Amy TTS$0.99
  • Ana TTS$0.99
  • Andy TTS$0.99
  • Ceitidh TTS$0.99
  • Lily TTS$0.99
  • Jordan TTS$0.99
  • Sam TTS$0.99
  • Nathan TTS$0.99

Questions

Is Sleep When I Sleep free?
Sleep When I Sleep is free to download, with in-app purchases available.
Is CerePlay free?
CerePlay is free to download, with in-app purchases available.
Which has better reviews, Sleep When I Sleep or CerePlay?
CerePlay is rated higher. Sleep When I Sleep averages 1.0 out of 5 from 2 ratings, while CerePlay averages 3.8 from 4 ratings.
Do Sleep When I Sleep or CerePlay have ads?
Neither Sleep When I Sleep nor CerePlay shows ads.
Which is updated more often, Sleep When I Sleep or CerePlay?
Sleep When I Sleep ships an update every 4 months, and CerePlay every 3 weeks. Most recently, Sleep When I Sleep was updated on October 6, 2026 and CerePlay on October 21, 2026.

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