# String Tension AI: Tennis — Measure. Track. Restring.

> Racquet string tension measurement and tracking tool using iPhone microphone. (iPhone/iPad app by Trader Prosperity LLC.)

- Source: https://appshunter.io/ios/app/string-tension-ai-tennis/id6763697805 (this page in markdown: same URL + `.md`)
- Developer: [Trader Prosperity LLC](https://appshunter.io/developer/1895443729)
- Category: Sports, Utilities
- Price: Free with in-app purchases
- Rating: 5.00/5 from 3 App Store ratings · 5 written reviews indexed
- Age rating: 4+
- Requires: iOS 17.0 · 83 MB
- Languages: American English, Danish, French (France), German (Germany), Italian, Brazilian Portuguese, Chinese (Simplified, China), European Spanish
- Released: 2026-05-03
- Data updated: 2026-10-14
- Monetization: freemium
- User reviews in markdown: https://appshunter.io/ios/app/string-tension-ai-tennis/id6763697805/reviews.md

## What is String Tension AI?

Measure tennis string tension. Make your next restring count.

String Tension AI is an iPhone app for measuring tennis string tension, tracking tension loss and choosing when to restring. Tap your racquet's stringbed near the microphone to get a tension estimate in kg or lb. No external hardware needed.

AVAILABLE IN 8 LANGUAGES

English, German, French, Italian, Spanish, Brazilian Portuguese, Simplified Chinese and Danish. The app follows your iPhone's language, with regional dates, numbers and currency. Choose a different app language in iOS Settings.

MEASURE AND TRACK FOR FREE

• Take unlimited measurements for one racquet and review your 20 most recent readings.
• Get live quality coaching, cross-checks across multiple taps and calibration against a known reference tension. Readings that do not hold up are set aside from guidance.
• Follow How to Measure with narration and captions in all eight languages.
• Check String Health, tension trends and restring guidance based on usable readings.
• Track full beds, hybrids, custom strings and separate main/cross tensions.

CONNECT YOUR PLAYING AND STRING HISTORY

• Log session duration, intensity and racquet; review the calendar, set goals, build streaks and celebrate milestones.
• Review and import tennis workouts from Apple Health for free, with possible duplicates flagged. Optional heart-rate access can suggest intensity without saving heart-rate data.
• Open My Stringers from the Strings hub to manage contacts, favorites, archives and restring history for free.
• Browse expanded racquet and string catalogs and ATP, WTA and Legends setups. Save favorite strings, add ratings and discover daily tennis facts.
• Share visual cards for supported string-health, tension, string-job and achievement highlights.

GO FURTHER WITH PRO

• Unlimited racquets and string setups, full measurement history and Measurement Insights.
• Advanced tension-decay analytics; compare racquets, strings and completed string jobs.
• Personalized string and hybrid recommendations using your playstyle, ratings and eligible retention history.
• Tension Advisor with What If scenarios for your equipment, game and conditions.
• Tension targets, optional alerts and Smart Detection for likely fresh strings or unusual tension changes.
• Playing-hours restring forecasts when enough dependable data is available.
• Automatic Apple Health import, detailed playing stats, advanced milestone tools and reminders.
• Cost Analytics, cost per playing hour, annual budgets, wishlist and stringer Annual Summary with PDF export.
• iCloud sync and PDF/CSV reports, including string-job reports for your stringer.

ASK STRING AI COACH

Ask about your racquet, tension, strings, playing history, restring timing and costs using your saved data. Questions, answers and racquet data stay on device. Available when the app is set to English, on compatible Apple Intelligence devices with iOS 26 or later, a supported system language and an available on-device model. Some questions require PRO.

READY WHEN YOU ARE

Check String Status widgets on your Home or Lock Screen. Use Siri, Shortcuts, Spotlight or the Action button to reach supported actions. Import, inspect and restore backups. Measurement audio is processed on device and never saved or uploaded; imported Health session records stay on your iPhone, outside iCloud sync and session exports. Shared summaries may include their totals. Optional analytics require consent.

Enjoy smoother measuring, browsing and sharing, more reliable history, forecasts, reports and sync, plus VoiceOver, Dynamic Type and Reduce Motion support. Requires iOS 17 or later.

Download free. Learn from every session. Restring with confidence.

Terms of Use: https://stringtensionai.com/terms/
Privacy Policy: https://stringtensionai.com/privacy/

## Key features

- Measure string tension with iPhone microphone
- Track tension decay over time
- Personalized restring recommendations
- String database and player setups
- Playing session tracking
- Cost tracking for restringing

## Pricing and in-app purchases

Base price: Free.

**Subscriptions**

| Subscription | Price | Period |
| --- | --- | --- |
| Annual PRO | $29.99 | per year |
| Monthly PRO | $4.99 | per month |

**One-time purchases**

| Purchase | Price | Type |
| --- | --- | --- |
| Lifetime PRO | $69.99 | one-time |


## Is String Tension AI safe?

Not enough ratings yet to assess String Tension AI.

## Is String Tension AI legit?

String Tension AI: Tennis has limited verification signals. The AppsHunter Legitimacy Score for String Tension AI is 58 out of 100 points across 7 verification signals from App Store and developer data.

## Recent user reviews (5 of 5)

All indexed reviews: https://appshunter.io/ios/app/string-tension-ai-tennis/id6763697805/reviews.md

### 5/5 — Much Improved

*2026-09-26*

When I originally tried the app, I had issues getting it to work. Since the update, there have been no issues. The interface is intuitive and well thought out. It allows you to enter key data about the strings and your setup. I have tried just about every tennis string tension app available, and String Tension AI has the best interface and excellent performance. String Tension AI is now my go to app to measure and track the tension of my string bed.

**Developer response:** We’re sorry you had this experience. We take performance reports seriously and continuously improve String Tension AI with frequent updates, extensive diagnostics, and 10,000+ automated tests. Apple’s Xcode reports show zero hangs across our last five releases, and our independent crash monitoring has likewise shown no recent widespread crash or freeze issues.

We also continue optimizing performance for older devices. If you’re using an iPhone 12 or older, please install the latest version, which includes additional compatibility and performance improvements.

String Tension AI is actively developed and is consistently updated with new features and reliability improvements on a regular basis. If you experience any issue, please contact us through the app or at stringtensionai.com so we can investigate it directly and help. We're always happy to help.

Thank you,
String Tension AI Team

### 5/5 — Much Improved

*2026-09-26*

After having a disappointing first use, and following a developer response, I gave the app another try. I have to say I was very impressed with the app. The layout is very intuitive, allows for excellent customization and entry of details. The developers, through their response to my concerns, have shown a strong desire to produce an excellent app that is both useful, but also very functional. I used it on an iPhone 11, and had no issues. Sting Tension AI is now my go to app to track the tension of my strings.

### 5/5 — General usability and effectiveness

*2026-08-28*

Love using the app. Has really helped me understand the best string type/tension for my specific racquet and play style and would definitely recommend. Looking forward to using it every time my string breaks 😂.

### 1/5 — Freezes

*2026-08-16*

Unfortunately, I never got to the point where I could test if this app can actually test my racket string bed tension. It requires you to set up the racket and string setup. It constantly froze. I finally gave up and deleted the app.

### 5/5 — Great for tracking string tension over time

*2026-05-15*

I’ve been using this for one month now and it's become part of my routine before matches. You just tap the strings and get a reading. What surprised me is how consistent the readings are when I tracked them over time. I like the chart readings and trends. I use Luxilon Alu Power and those strings lose tension fast, so being able to actually see the drop over a week or two is really useful for knowing when my strings are dead and impacting my game. After getting my racquet restrung I calibrated it in the app and the absolute tension numbers lined up pretty well too. There's also a section where you can see what strings and racquets the pros use which is fun to browse. Can't believe this is free honestly. Wish I found it earlier.

## Frequently asked questions about String Tension AI

### How does String Tension AI measure string tension?

String Tension AI uses your iPhone's microphone to analyze the sound produced when you tap your racquet strings. The app then processes this sound to calculate the current tension of your strings.

### What are the benefits of the Pro version of String Tension AI?

The Pro version unlocks advanced features like full analytics and decay charts, a tension advisor, string recommendations, hybrid string builder, cost analytics, detailed playing stats, milestones, iCloud sync, and PDF/CSV export.

### Can I use String Tension AI on multiple devices?

Yes, with the Pro version, iCloud sync is available, allowing you to keep your data across all your devices seamlessly.

### How often is String Tension AI updated?

The app was last updated on 2026-06-22, indicating regular updates to improve features and reliability. The latest version is 2.13.

### What is the age rating for String Tension AI?

String Tension AI has an age rating of 4+, making it suitable for a wide range of users.

### Does String Tension AI have ads?

No, String Tension AI does not contain advertisements. The app is ad-free.

### What kind of reports can I export from String Tension AI?

With the Pro version, you can export detailed PDF and CSV reports. You can also send string job reports directly to your stringer.

### How does String Tension AI compare to a physical string tension meter?

String Tension AI offers the convenience of using your iPhone's microphone, eliminating the need for external devices. It also provides advanced tracking, analysis, and personalized recommendations that physical meters may not offer.

## Version history (last 5 releases)

### 2.35 — 2026-10-10

String Tension AI 2.35 gives clearer feedback in the iOS tennis racquet and string-tension tracking app when exports, saves, Apple Health connections or notifications cannot complete. PRO features explain when your subscription cannot be confirmed, and messages remain visible on the screen you are using.

App Store Release Notes
- Clearer messages when exports, racquet photos, backup deletion or saving changes cannot complete.
- Status and error messages stay visible on the screen you are using, including open sheets and detail screens.
- PRO features tell you when your subscription cannot be confirmed, so you know when to try again.
- Apple Health explains when connecting fails or a Keep or Remove choice cannot be saved.
- Improved Apple Health imports.

### 2.34 — 2026-10-05

String Tension AI 2.34 makes it easier to keep track of the people who string your racquets. Open My Stringers directly from the Strings hub to manage contacts, favorites and restring history, whether you use Free or PRO. A stringer's Annual Summary, including PDF export, now requires PRO, with clearer access and export progress.

The How to Measure video has refreshed English narration with more even volume between lines. Dashboard figures, racquet health, Compare Racquets and Tension Advisor guidance stay current when the reliability of a saved reading changes. Stringer screens handle records removed through iCloud sync more safely, and clearer delete guidance helps you preserve stringer history. Existing data is preserved during a normal upgrade; optional analytics continue to require consent.

App Store Release Notes

- Open My Stringers directly from the Strings hub. Manage contacts, favorites and restring history with Free or PRO.
- Review a stringer's year with Annual Summary and export it as a PDF with PRO. Export progress helps prevent repeated taps from opening duplicate reports.
- Refreshed English narration, new German, Italian, Spanish, French, Danish, Brazilian Portuguese and Simplified Chinese narration and more consistent voice volume make How to Measure easier to follow.
- Dashboard figures, racquet health, Compare Racquets and Tension Advisor guidance update more reliably when a saved reading's reliability changes.
- Stringer details, editing and annual summaries close safely if iCloud sync removes the stringer.
- Clearer delete guidance explains what happens to past restrings and when to archive a stringer to keep that history.

### 2.33 — 2026-10-01

String Tension AI 2.33 improves smoothness and responsiveness across the #1 iOS tennis racquet and string-tension tracking app, helping Free and PRO players spend less time waiting and more time checking their strings. Dashboard, History, racquet details and string tools are smoother to use with long histories. Measuring, adding notes and sharing results are more responsive, with lighter visual effects on older supported devices and in Low Power Mode.

The catalog adds 100 racquet models from Babolat, Diadem, Dunlop, Head, Prince, ProKennex, Solinco, Tecnifibre, Volkl, Wilson and Yonex, plus 28 strings from Babolat, Diadem, Dunlop, Head, Luxilon, reString, Solinco, Tecnifibre and Yonex, making it easier to find your equipment. Custom brand entry supports strings outside the list. PRO users can reach Cost Analytics directly from Cost Summary, while clearer plan pricing helps players compare purchase options. Forecast, History, widget and iCloud sync fixes make everyday tracking more dependable. Existing data is preserved with no upgrade steps required

### 2.32 — 2026-09-27

String Tension AI 2.32 gives users of the #1 iOS tennis racquet and string-tension tracking app a narrated How to Measure video with localized captions, more accurate string-job history, and clearer spending by currency. Apple Health import review remains free on supported devices, while automatic import remains a PRO feature. The Tension Advisor now keeps recommendations consistent across restrings; personalized advice continues to require PRO.

Calibration and tension forecasts handle changes in the calibration used for a set of strings, and Apple Health sessions that may duplicate a manual log are easier to review. Exports, reminders, purchase restore, recovery and iCloud sync are more reliable. Existing data is preserved during a normal upgrade; the release includes a lightweight local data migration and already deployed iCloud schema additions. Optional diagnostics continue to respect analytics consent.

App Store Release Notes
- Learn to measure with the narrated How to Measure video, localized captions, playback controls and Skip.
- Past string jobs imported from Apple Health stay in history without replacing current strings; backdated restrings assign playing sessions to the strings used on those days.
- Tension Advisor recommendations no longer drift just because you followed earlier advice and restrung again. Split-tension setups apply the suggested change to both sides.
- Calibration and forecasts use readings from the current calibration; older strings ask you to enter a current reference tension.
- Spending and comparisons keep different currencies separate. Cost per day uses completed string jobs with recorded prices.
- Possible duplicate Apple Health sessions are flagged for review, and automatic import resumes more reliably after PRO is renewed.
- CSV and PDF reports are easier to use, with clearer split tensions, improved racquet QR links and better spreadsheet compatibility.
- Restore Purchases shows progress and a clear result. Reminders, backups and iCloud sync are more reliable, and measuring stays responsive while the microphone starts.

### 2.31 — 2026-09-20

String Tension AI 2.31 makes measurement and calibration startup more responsive for Free
and PRO users of the iOS tennis racquet and string-tension tracking app. History, racquet lists,
Dashboard statistics, baseline-reminder checks and string-setup editing also do less repeated work,
while synced changes now refresh History, comparisons, Playing Stats and string-health results more
reliably. String-setup identity remains protected if sync changes a setup while its edit form is open. 

App Store Release Notes
- Measurement and calibration startup stay responsive while iOS prepares the microphone.
- Leaving the app while a measurement is starting now reliably stops it.
- History and racquet lists do less repeated work, especially for long measurement libraries.
- Dashboard statistics, baseline-reminder checks and string-setup editing are more efficient.
- Synced changes now refresh History, comparisons, Playing Stats and string-health results more
reliably.
- String details remain protected if a synced reading arrives while their edit form is open.

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*Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-10-14.*