Comparison

String Tension AI vs Stringbed

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

Head to head
About

String Tension AI

This app uses your iPhone's microphone to measure the tension of your racquet strings. It tracks tension decay over time, offers personalized restring recommendations, and provides a comprehensive string toolkit for serious players.

Highlights
  • 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
Features
Read full description

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/

About

Stringbed

Features
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Which string to ask for, and how many pounds — for your racket and the way you play. Answer a few plain questions; “I don’t know” always counts. Your first number is free; the string to ask for and unlimited answers come with one payment. No subscription. No account. Nothing collected by us. HOW IT GOES You answer a few plain questions: how you hit, how often you play, what is in the racket now, whether your arm bothers you afterwards. A band on a fixed 40–62 pound scale narrows while you answer, so you can watch the answer being found. “I don’t know” is a real answer at every step — the app keeps it as unknown and widens the band instead of guessing quietly. When there is enough to settle, the band lands on a number and you get: • the exact pounds for the up-and-down strings and for the side-to-side strings • with Unlimited answers: one string to use, named with its thickness and the reason, plus up to two alternatives • one sentence to say at the counter • “Why these numbers” — which of your answers moved the number, and by how much • what the app still does not know, and how far that moves the middle TELL IT HOW IT PLAYED, AND THE NEXT NUMBER LISTENS After you play the bed, say how it felt — too harsh, too soft, or just right — and whether the strings broke fast. Your next answer for that racket moves by a small, bounded step and says why in one line. Strings that keep breaking point you to a thicker gauge. When a restring is due, the Rackets screen says so (no notifications). THE SAME ANSWERS ALWAYS GIVE THE SAME NUMBER The number comes from a built-in model of how a string bed behaves: head size, string pattern, frame stiffness, string material and thickness. It does not drift with how you phrase things and it does not change its mind overnight. That is the point — it gives you one steady starting point, and from there you can go a pound up or a pound down and find what you like. TYPE IT AND THE RACKET DRAWS ITSELF Type what is printed on your frame. There is no long list to scroll: as the letters agree, the racket narrows down to itself, and what the app knows about it — head size, string pattern, the range printed on the frame — appears with the page it was read from. If it cannot find your racket, it says so plainly and asks how the racket feels to hit instead. EVERYTHING IS ALREADY INSIDE 165 racket models and 195 strings ship inside the app, every row carrying the published page it came from (Settings → Sources). Every answer is worked out on your iPhone from data built into the app. The only thing that needs the internet is an optional web search for the string you were given, and you decide whether to tap it. WHAT IT COSTS Free to download. Your first settled answer — the pounds and why — is free. The string to ask for, and every answer after that, open with one payment, forever — not a subscription, no credits, nothing metered, nothing to renew. Restore Purchases sits in Settings. Recording what you actually had strung, and how it played, is free before and after any purchase. WHAT IT KEEPS Nothing reaches us. There is no account, no sign-in, no analytics, no advertising and no server of ours anywhere. What you enter stays on your devices. If iCloud is on, it syncs through your own private iCloud account — we could not read it if we tried. The only thing the app opens outward is a web search for the string, in Safari, with no tracking added and no affiliate link; we earn nothing from it and get nothing back. FOR THE PLAYER, NOT FOR THE SHOP Tension, thickness and string type are explained in ordinary words before they are ever named. If you have never chosen a string in your life, you can still answer every question honestly — including “I don’t know”. This is about your strings, not about your health. If pain keeps up after a softer setup, see a doctor.

Screenshots

String Tension AI4 screens
Stringbed4 screens

Verdict

The call

String Tension AI and Stringbed are too close to call on the numbers: across 6 compared parameters — price, update cadence, ads and in-app purchases among them — neither pulls far enough ahead to decide it. What separates them is feature set and interface, not measurable difference.

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. String Tension AI sells 3 in-app purchases, starting at $4.99 per month and Stringbed sells 1 one-off in-app purchase. Whichever you choose, the download price is not the number that matters.

UpkeepUpdate frequency

String Tension AI ships an update every 4 days, Stringbed every 5 days. The most recent releases landed on October 31, 2026 and November 6, 2026 respectively.

ScorecardNo meaningful differences
String Tension AI versus Stringbed: the parameters behind the verdict, then further details
ParameterString Tension AIStringbed
PriceFreeFree
Rating5.0 (3 ratings) — better—
Positive reviews80.0% of reviews—
Number of ratings3 — better—
Update frequencyEvery 4 days — betterEvery 5 days
AdsNoNo
In-app purchasesYesYes
MonetizationFreemium—
DevicesiPhoneiPhone
Requires iOS17.017.0
Further details — not scored
Size84 MB7 MB
Age rating4+4+
DeveloperTrader Prosperity LLCLaure Shin

In-app purchases

3 purchases

String Tension AI

Subscriptions2
  • Monthly PRO$4.991 Month
  • Annual PRO$29.991 Year
One-time1
  • Lifetime PRO$69.99
1 purchases

Stringbed

One-time1
  • Unlimited answers$14.99

Questions

Is String Tension AI free?
String Tension AI is free to download, with in-app purchases available.
Is Stringbed free?
Stringbed is free to download, with in-app purchases available.
Do String Tension AI or Stringbed have ads?
Neither String Tension AI nor Stringbed shows ads.
Which is updated more often, String Tension AI or Stringbed?
String Tension AI ships an update every 4 days, and Stringbed every 5 days. Most recently, String Tension AI was updated on October 31, 2026 and Stringbed on November 6, 2026.

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