Tensi app icon

The quiet patterns behind how you feel.

Tensi correlates your calendar, places, weather and body signals — HRV, sleep, heart rate — analysed on your iPhone and Apple Watch. We run no servers and never receive your data.

Get Tensi on the App Store See how it works

Available now on the App Store · iPhone & Apple Watch

Analysed on-device No account required No ads, no trackers Works with Apple Watch
Tensi on iPhone and Apple Watch, showing today's recovery status
Tensi Today screen: understand your daily recovery Tensi Patterns screen: connect your life to your health Tensi pattern detail: meetings and recovery connection Tensi Body screen: health metrics and explanatory charts Tensi pattern detail: place-related findings Tensi Weekly Report screen Tensi on iPhone and Apple Watch together
Features

Everything, quietly connected.

Tensi doesn't just show your numbers — it notices what they have in common with the rest of your life.

Today

Your vitals at a glance — HRV, resting heart rate and an overall sense of how today is going, the moment you open the app.

Patterns

Tensi looks for real correlations — back-to-back meetings, a rainy week, a recurring place — against how your body actually responded.

Body

Sleep, activity, respiratory rate, cardio fitness and more, organized into one clear picture instead of scattered Health tiles.

Recovery & Calendar

A day-by-day recovery calendar so you can see, at a glance, which stretches asked the most of you — and which let you recharge.

Weekly Report

A short, honest summary of the week — trends worth knowing about, delivered without the noise of a full dashboard.

Built for Apple Watch

A native watchOS companion with its own widgets and complications, so today's HRV trend is always one glance away.

Privacy

Private by design, not by policy.

Tensi was built with a simple rule: your health, location and calendar data never leave your device. Not to us, not to anyone.

Everything is processed on-device Correlations are computed right on your iPhone. Nothing is uploaded to a server — because we don't run one.
No account, ever There's nothing to sign up for and nothing tied to your identity. Tensi doesn't know who you are.
Calendar: counts only Tensi reads meeting counts and durations to spot busy stretches. Titles, notes and attendee names are never read.
Location: never an address Recurring places are noticed on your iPhone to find patterns. Coordinates go only to Apple's own weather and place-name services, never to us.
No ads, no analytics, no trackers Tensi has no advertising SDK, no analytics SDK, and no third-party code of any kind watching what you do.
Not a medical device Tensi surfaces patterns for your own awareness. It doesn't diagnose or treat anything, and isn't a substitute for medical advice.

Read the full Privacy Policy for details.

Pricing

Free to start. Simple to upgrade.

Today's vitals are free, always. Tensi Pro unlocks the full correlation engine.

Free
$0
forever
  • Today's HRV & resting heart rate
  • Body metrics overview
  • Apple Watch app & widgets
Get Started
Tensi Pro
$1.99/mo
or $11.90 billed yearly
  • Everything in Free
  • Full Patterns correlation engine
  • Recovery calendar & history
  • Weekly Reports
Start with Tensi Pro

Auto-renewable subscription, managed through your Apple ID. Cancel anytime in Settings.

FAQ

Questions, answered.

What does Tensi actually do?
Tensi looks for real correlations between your life — meetings, recurring places, weather — and your body's own signals, like HRV, sleep and resting heart rate. Instead of just showing you charts, it tells you which parts of your day actually line up with how you felt.
How does Tensi actually calculate a pattern?
For each pair — say, meeting load and HRV — Tensi compares the days a condition was present against the days it wasn't, and checks whether the difference is both large enough to matter and consistent enough to trust. It needs roughly 10 or more matching days before it will surface anything at all, and only shows the handful of strongest, most reliable findings — never every coincidence that happens to clear a low bar.
What do the STRONG / MODERATE / WEAK labels mean?
They summarize how reliable a finding is, based on how large the difference is and how consistent it's been across your own data — not a single unusual day. STRONG means a large, consistent effect. MODERATE means a real but smaller one. WEAK means a pattern worth watching, not yet conclusive.
What's the difference between RMSSD and SDNN?
Both measure heart rate variability from the same heartbeat data, just calculated differently. RMSSD is more sensitive to short-term, moment-to-moment changes; SDNN reflects variability over a longer window. Tensi shows both so you can look at the same story from two angles, alongside resting heart rate, sleep, activity and your other supported health data.
What does "the next day" or "2 days later" mean in a finding?
That's the lag between cause and effect. If a finding says a busy day correlates with lower HRV "the next day," Tensi is comparing what happened on day X against your HRV on day X+1, not the same day — some effects on the body show up with a delay, and Tensi checks for that rather than assuming everything is same-day.
Does Tensi diagnose or treat anything?
No. Tensi surfaces patterns for your own awareness — it isn't a medical device, doesn't diagnose conditions, and doesn't provide treatment or medical advice. For anything health-related, talk to a qualified professional.
Does any of my data leave my phone?
No. Every correlation is computed on your iPhone. Tensi has no backend server, no account system, and no analytics or advertising SDKs, so we never receive your data. The only thing that leaves your device is location coordinates sent to Apple's own weather and place-name services.
What permissions does Tensi need, and why?
Health data (like HRV, sleep and heart rate) to compute correlations; Calendar, read as event times, durations, recurrence, attendee counts and location presence, never titles, notes or attendee names; and Location, to notice recurring places and fetch local weather. All optional, all analysed on your iPhone.
Does Tensi work with Apple Watch?
Yes. Tensi ships with a native watchOS companion app plus its own widgets and complications, so today's HRV trend is always on your wrist.
What's the difference between Free and Pro?
Free gives you today's vitals, the body metrics overview, and the full Apple Watch app. Tensi Pro unlocks the full Patterns correlation engine, the Recovery calendar and history, and Weekly Reports.
How much does Tensi Pro cost, and can I cancel?
Tensi Pro is $1.99/month or $11.90/year, billed through your Apple ID as an auto-renewing subscription. You can cancel anytime from Settings → Apple ID → Subscriptions on your device — no need to contact us.
Does Tensi show ads or sell my data?
No. There are no ads anywhere in Tensi, and there's no data to sell in the first place — nothing is collected off your device.
What languages does Tensi support?
English, German, Spanish, French, Japanese, Turkish and Simplified Chinese, with more planned.
I have feedback or found a bug — how do I reach you?
Reach out any time at burakoztirpan@gmail.com — or see the contact page.

Start noticing the patterns.

Free to download. Nothing to sign up for.

Get Tensi on the App Store

What is Tensi?

Tensi is a stress and HRV (heart rate variability) tracker for iPhone and Apple Watch. It connects your calendar, the places you visit, the weather and your sleep with HRV and resting heart rate from Apple Health, so you can see which meetings, days and habits drain you and which help you recover. All analysis runs on your device, with no account and no server.

Download Tensi: Stress & HRV Tracker on the App Store

Is there an app that shows which meetings stress me out?

Yes. Tensi compares your calendar with heart rate variability and resting heart rate from your Apple Watch. Over time it shows patterns such as back-to-back meetings or long workdays that line up with lower HRV, so you can see which parts of your schedule cost you the most.

How does Tensi measure stress?

Tensi uses heart rate variability (HRV) and resting heart rate recorded by Apple Watch and stored in Apple Health. Lower HRV than your personal baseline usually signals more stress or less recovery. Tensi then looks for correlations with your calendar, places, weather and sleep.

Does Tensi work with Apple Watch?

Yes. Tensi has a native Apple Watch app with widgets and complications, so today's HRV trend is one glance away. It reads data through Apple Health on your iPhone.

How is Tensi different from other HRV apps?

Most HRV apps show your numbers. Tensi focuses on why they change: it correlates HRV with your calendar, locations and weather to surface the meetings, places and routines linked to stress and burnout.

Is Tensi free?

Tensi is free to download, and today's HRV and resting heart rate are free forever. Tensi Pro ($1.99 per month or $11.90 per year) unlocks the full pattern engine, the recovery calendar and weekly reports.

Is my health data private?

Yes. Your health, calendar and location data stay on your iPhone. Tensi has no account and no server, so the developer never receives your data.

By Burak Öztırpan · Last updated: November 2026