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— Case study · Garmin watch app

Garmin watch app case study

Sauna Sessions is a Garmin watch app for sauna, steam and plunge sessions. It runs on the watch, times every stage, and saves each session to Garmin Connect. Outlap designed it, built it, tested it and listed it in the Connect IQ Store, along with the page and the card checkout that sell its Pro unlock.

01 · The brief

What did this project involve?

Build a watch app that runs a whole sauna session from the wrist: guided protocols that advance on their own, a free-form timer for everything else, and a proper activity in Garmin Connect at the end. Then sell a Pro unlock for it with no account system and no subscription.

A sauna is a bad place for a phone and a worse one for a touch screen. The app had to work from the watch's buttons with wet hands, keep time through heat and cold stages without anyone watching it, and lose nothing if it restarted halfway through a session.

It went from first commit to store submission in two days. The changelog then lists six releases in seven days, from a transition countdown between stages to a touch lock for wet fingers.

02 · The app

What does the app do?

It times sauna, steam, plunge and recovery sessions on the watch and saves each one as a FIT activity with a lap per stage. There are 7 guided protocols and a free-form timer that covers 13 session types. Heart rate and the watch's temperature readings are recorded along the way.

In a guided protocol the watch counts each stage down, vibrates and beeps at the change, and moves on by itself. A 60-second transition countdown sits between stages, it can be set anywhere from 0 to 600 seconds, and START skips it. Next stage and Extend +1 min are in the pause menu.

Sessions are recorded as a Mobility activity named after the protocol, or as Breathwork on a watch that refuses Mobility. The full name is also kept inside the file, in case Garmin shortens the title. In the file, each stage is a lap that carries its planned and actual seconds. Temperature is sampled every 30 seconds, and the site is tagged by GPS when the watch is within 150 metres of a known venue.

The app is plain about what it cannot do. Wrist temperature is the air at your wrist, not the room. Humidity is not measured, because Garmin gives apps no sensor for it, and the file says "unavailable" instead of inventing a number.

The free app includes all 7 protocols. Pro is a one-off $9.99 unlock that adds your own protocol templates, typed into Garmin Connect or built on the watch, and free-text notes. One code per watch, and it does not expire.

The web half is ours too: the Sauna Sessions page, the card checkout, and the page that hands the buyer their code after payment.

03 · The proof

How do these panels prove it?

The panels below are drawn from the app's own source: the stage tables the watch runs, the exact words it shows when a sensor or a save fails, and the unlock steps a buyer goes through. Nothing below is a mock-up.

A watch app has no web page to lift a chart from, so the data was lifted instead. Protocol names, stage minutes and on-screen strings are verbatim. The running screen itself is drawn on the Garmin device apps page.

Seven protocols — one time scaleLifted data
GUIDED PROTOCOLS · 7 BUILT IN · ONE LAP PER STAGE Default stage minutes · the watch moves to the next stage on its own heatcoldcontrast · compression Nordic AMNordic PMExpressRefreshNomadAfterburnRecover 53 min53 min25 min40 min50 min65 min40 min Sauna 20 · cold 3 · hot 2 · cold 3 · Steam 20 · Cold plunge 5Sauna 20 · cold 3 · hot 2 · cold 3 · Steam 20 · Hot plunge 5Sauna 20 · Cold plunge 5Sauna 20 · Contrast 20Compression 30 · Contrast 20Infrared 45 · Contrast 20Steam 20 · Contrast 20 0204060 min The same stage tables the watch runs. All seven are in the free app.
Failure cases — what the watch doesLifted data
FAILURE CASES · WHAT THE WATCH DOES Each case has its own simulator test · 52 tests, 52 passed NO HEART-RATE SENSORScreen shows HR -- · nothing else changes NO TEMPERATURE READINGShows temp -- · the file leaves it unavailable, never zero NO GPS FIX BEFORE THE TIMEOUTSite tag reads Ad hoc · a GPS error is ignored, never raised APP RESTARTS MID-SESSIONCheckpoint every 5 s · Home offers Resume / Discard · stage times carry over STORAGE WRITE FAILSThe failed write is reported, not thrown · the running session is untouched FIT SAVE FAILSSummary says FIT save failed · checkpoint kept · Save can be retried Discard always sits behind a confirmation. While a session runs the screen ignores taps and swipes. Buttons only.
Pro unlock — watch and webLifted data
PRO UNLOCK · ONE CODE PER WATCH The watch half and the web half, built together ON THE WATCHHome → START → Pro shows an 8-character device ID CARD CHECKOUTThe buyer types that ID in at checkout and pays once SUCCESS PAGEThe code appears straight after paymentXXXX-XXXX-XXXX-XXXX · the receipt links back to the page GARMIN CONNECTThe code goes into the app's settings, once ON THE WATCHThe watch checks the code itselfno server call · a settings re-sync cannot re-lock it $9.99 once · one code per watch · it does not expire No account. No subscription.

— Real app data, rebuilt as vectors.

04 · The checks

How was the app tested?

In Garmin's simulator, against real device profiles, before it went near a wrist. The current build runs 52 unit tests and all 52 pass. The app declares 25 watch models across the fēnix, epix, Venu and Forerunner ranges, and the release package builds for every one of them.

The tests drive every protocol through all of its stages to the summary screen and run a free-form start, pause, resume and stop. Then they break things on purpose: no heart-rate sensor, no temperature reading, a GPS timeout, a restart mid-session, a storage failure and a failed FIT save. Each case has to end with no crash and no lost session.

Permissions are declared up front, and the app asks for five: FIT recording, FIT developer fields, positioning, sensors and sensor history. It collects no user data. Everything stays on the watch and in the owner's own Garmin Connect account.

05 · Cost and timeline

What does a Garmin app cost?

There is no list price for Garmin work. A single data field is not the same job as a full session app with protocols, a settings layer and a paid unlock, so every app gets a fixed quote from its brief, and we reply within 2 business days.

Essentials $599/ Marketing site from $1,490/ Online store from $1,490/ Web app from $4,900/ White-label talk to us

Those are the web tiers, and the full ladder is on the pricing page. Garmin work sits beside them and is quoted the same way. If the app needs a landing page, a checkout or an unlock page, that is web work and the same studio builds it.

On timeline: this app went from first commit to store submission in two days.

06 · The takeaway

What does this prove for your app?

One studio can design, build, test and list a watch app, and build the web side that sells it. If you have a device app, a data field, a widget or a watch face in mind, that is one brief here.

How the work runs is on the Garmin device apps page, and the app itself is at Sauna Sessions. The web portfolio is built the same way: the health-tracking case study, the plan simulation case study and the online store case study.

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Email your Garmin app brief: what it has to do and which devices it must run on. A fixed quote follows it, and we reply within 2 business days.

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