SleepMi vs Letterly
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
SleepMi
This app focuses on improving sleep quality through intelligent wearable devices and comprehensive data analysis. It aims to leverage technology for a better sleep experience.
- Intelligent wearable device integration
- Comprehensive sleep data showcasing
- Technology-driven sleep enhancement
- Improved user experience for sleep
- Deep software integration
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Sleep well, use valuable meters! Value Mi Sleep, focusing on the sleep field, enhances user experience through self-developed intelligent wearable devices and deep integration with software, showcases data comprehensively, and looks forward to technology changing sleep and bringing you a better sleep experience!
Letterly
Instantly transform your speech into polished text for notes, messages, social media, and more. Organize with custom tags, use offline, and choose from over 25 rewrite styles. Supports over 90 languages and syncs across all your devices.
- Speech to text transcription
- Customizable text rewriting
- Note organization with tags
- Offline recording
- Multi-language support
- Cross-device syncing
- Audio file upload transcription
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Turn your speech into brilliant text – instantly. Write anything, anytime. Perfect for notes, messages, emails, meeting summaries, journal entries, social media posts, and much more. Find your own unique use case! HOW IT WORKS This isn’t just a transcription tool. Just record any speech, and get polished, ready-to-use text immediately. USE CASES - Note-taking: ideas, to-dos, shopping lists, plans - Communication: messages, emails, comments - Content creation: social media posts, articles, newsletters, scripts - Journaling: thoughts, emotions, memories, gratitude - Meetings: summaries, minutes, action plans USEFUL FEATURES - Tags: organize notes with custom tags for easy navigation - Offline mode: capture thoughts anytime, even without internet - Any device: iPhone, Web, Mac, or iPad – notes stay synced across all platforms - Rewrite options: choose from 25+ premade rewrite styles or create your own - 90+ languages: speak freely – language is detected automatically - Widget: start recording instantly from your home screen - Translate: convert voice notes to any language in seconds - Quick sharing: send your text anywhere via Share button or integrations like Zapier - Audio upload: transcribe recordings made outside the app - Long recordings: record up to 90 minutes per note with unlimited recordings Download and try it today! We’ve designed the app to be simple, intuitive, and perfect for daily use. Terms of use: https://www.apple.com/legal/internet-services/itunes/dev/stdeula
Screenshots
Verdict
The clearest difference is in-app purchases: SleepMi at none against Letterly's 9. SleepMi also leads on iOS requirement (9.0 vs 16.0). Letterly's advantage is update cadence (every 10 days vs every 3 months) and review sentiment (78% vs 50%). On price and ads 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
Both are free to download. Letterly sells 9 in-app purchases, starting at $19.99 per month. SleepMi asks for nothing beyond the download.
SleepMi ships an update every 3 months, Letterly every 10 days. The most recent releases landed on October 6, 2026 and October 27, 2026 respectively.
| Parameter | SleepMi | Letterly |
|---|---|---|
| Price | Free | Free |
| Rating | — | 4.7 (1.1K ratings) — better |
| Positive reviews | 50.0% of reviews | 78.1% of reviews — better |
| Number of ratings | — | 1.1K — better |
| Update frequency | Every 3 months | Every 10 days — better |
| Ads | No | No |
| In-app purchases | No — better | Yes |
| Monetization | Free — better | Free with in-app purchases |
| Devices | iPhone, iPod | iPhone, iPad, Mac, Apple Watch — better |
| Requires iOS | 9.0 — better | 16.0 |
| Further details — not scored | ||
| Size | 11 MB | 95 MB |
| Age rating | 4+ | 4+ |
| Developer | Shenzhen LINGXI Technology Co., Ltd | Anton Lebedev |
Customer experience
SleepMi
Letterly
Bugs and requests
SleepMi
Not enough reviews yet to summarise bugs or requests.
Letterly
Reported bugs
3 issues- Login screen freezes
- Incompatible with older devices
- When I get phone calls, I lose the entire recording
Requested features
3 requests- Dark mode option
- Advanced analytics dashboard
- Ability to use the artificial intelligence to search through all of my old notes for similar topics or keywords
In-app purchases
SleepMi
No in-app purchases
Letterly
- PRO Subscription (1 month)$19.991 Month
- PRO Subscription (3 months)$44.903 Months
- PRO Subscription (1 Year)7 Days trial$69.991 Year
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- PRO Subscription (1 Year)7 Days trial$79.991 Year
- PRO Subscription (1 Year)7 Days trial$89.991 Year
- PRO Subscription (12 months)7 Days trial$99.991 Year
- PRO Subscription (12 months)14 Days trial$99.991 Year
- PRO Subscription (Lifetime)$199.99
- PRO Subscription (Lifetime)$249.99
