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50 founding slots

Polar API integration

Vantage, Grit X and Pacer training sessions, delivered to your server as they finish — without registering an AccessLink client, and without the three-call transaction dance Polar makes you do to read them.

Live today for connections and activities. Three days free, then $20 a month, flat — no per-athlete fee.

All integrations

link a polar athlete — no polar credential involved

// Your own id for your own user. You hold no polar client secret.
const link = await stridee.post('/v1/connect', {
  provider: 'polar',
  external_user_id: 'user_4821',
  return_uri: 'https://app.yourapp.com/settings/devices',
});

// Redirect their browser. Good for 30 minutes.
res.redirect(link.connect_url);

Deliveries

What you get when a Polar workout finishes

An activity.created event carrying Polar’s own summary, sealed to your public key. The FIT file isn’t in it — that is a pre-signed provider URL that expires, because re-hosting your athletes’ activity files is a retention decision rather than something to slip into a webhook payload.

  • Sport as Polar classified it, mapped onto one vocabulary
  • Start time, duration and the Polar exercise id
  • The device the session came off
  • A pre-signed URL to the Polar FIT file, which expires

Polar AccessLink

The Polar integration you’re not writing

Polar’s own developer API, reached by registering a client at admin.polaraccesslink.com. It is the most self-service programme of the four — and the most awkward to actually read data from.

01

Register the user with Polar, separately

AccessLink is not done when OAuth is done. After the athlete authorises, you make a further call to register them against your client before Polar will give you anything — a step that has no equivalent at any other provider, and a step whose failure mode is a connected user who silently returns no data.

02

Then commit a transaction to read anything

Polar does not simply let you list exercises. You create a transaction, read the list it pins, fetch each item, and then commit the transaction to mark it consumed — and if you crash between the fetch and the commit, you re-read; if you commit early, the data is gone. It is a genuinely stateful read protocol, and it is the single most common reason a Polar integration ships late.

03

And stay inside the rate limits

AccessLink meters you, so a naive implementation that polls per user per minute stops working at exactly the point your product starts working. We hold that budget on one client across every developer, and you hold none of it — you get a push when a session finishes and write no polling loop at all.

What replaces all of it

One POST /v1/connect naming polar, and a webhook handler you write once for every provider. The registration is ours, the consent screen is ours, and the token refresh is ours.

Connecting a device

link a polar athlete — no polar credential involved

// Your own id for your own user. You hold no polar client secret.
const link = await stridee.post('/v1/connect', {
  provider: 'polar',
  external_user_id: 'user_4821',
  return_uri: 'https://app.yourapp.com/settings/devices',
});

// Redirect their browser. Good for 30 minutes.
res.redirect(link.connect_url);

Coverage

What Polar does, and what it doesn’t yet

Nothing below is marked live unless an endpoint serves it today. Where Polar doesn’t send something, the field is absent rather than estimated — a null you can branch on is worth more than a number nobody measured.

  • ConnectLive today
  • ActivitiesLive today
  • Daily summariesDesigned, not yet shipped
  • Workout pushDesigned, not yet shipped

Devices

Which Polar devices are covered

The integration is with the athlete’s Polar account rather than with a watch, so anything that syncs into it reaches you — including models released after you shipped, with no change on either side.

Performance

  • Vantage V3
  • Vantage M3

Outdoor

  • Grit X2 Pro
  • Grit X2 Pro Titan
  • Grit X2

Running

  • Pacer Pro
  • Pacer

Everyday

  • Ignite 3
  • Unite

Sensors

  • H10 heart rate sensor
  • Verity Sense

Pricing

Flat, and not per athlete.

A unified wearable API normally costs hundreds of dollars a month and meters every connected user on top — so the moment your product works, your bill grows with it. This is $20 a month for the whole API, whatever you connect.

$20

per month, flat

Every provider and every endpoint. Three days free first, and cancelling is a button in the Stripe billing portal.

No per-athlete fee

connect as many as you like

The bill is the same at ten connected athletes and at ten thousand. There is no credit balance to watch and no overage to model.

No approval queue

checkout is the signup

You are not applying to Polar AccessLink. Paying creates the account and opens the console, automatically, in the seconds it takes Stripe to tell us.

Founding 50

Three days free. Then $20 a month.

The private beta is open, and checkout is the whole signup — pay and your account exists, with the console switched on, before you have finished reading the receipt. No waitlist, no sales call, and nobody approving you.

  • Keys the moment checkout finishes — no waitlist, no approval
  • Garmin, COROS, Polar and Wahoo behind one connect call
  • $20/month for the whole API — every provider, every endpoint
  • One of only 50 founding slots, and the price they keep
  • A private Discord channel with the engineers who wrote the integrations
  • A vote on what we build next — the founding 50 order the roadmap

Cancel in one click from the billing portal, at any point in the three days or any month after. If something goes wrong on our side, email hi@stridee.fit and we refund you. No forms, no conditions.

Founding slots

50

Only 50 founding slots exist. When they are gone, they are gone.

$20/month — after 3 free days

Card required, nothing charged for three days. Flat rate for the whole API, not per connected athlete.

Start building — free for 3 days

Stripe checkout · cancel any time · keys the moment it clears

What happens next

01

You pay

Stripe collects the card. Three days free first, then $20/month, and cancelling is a button in the same billing portal.

02

We create your account

Against the email you paid with, automatically, the moment Stripe confirms. Nobody reviews it.

03

You log in

platform.stridee.fit/login, same email, code in your inbox. Mint a signing key and your first call works.

Already bought and want the console? platform.stridee.fit/login

Not ready to claim?

Come talk to us in Discord first. We answer questions there before anywhere else.

Join the Discord

Polar API questions

No. That is the point of the integration. We hold the Polar AccessLink registration, the client credentials and the redirect URI; you call POST /v1/connect with your own id for your own user and redirect their browser to the URL that comes back. There is no Polar secret in your environment, no callback route in your router, and no approval queue between you and your first connected athlete.

Three days free, then $20 a month, flat — for the whole API, every provider and every endpoint, with no per-athlete metering. The usual price for a unified wearable API starts in the hundreds of dollars a month and charges again for each connected user, which is a pricing model that punishes exactly the thing you are trying to do. Cancel from the Stripe billing portal whenever; access ends when the period does.

You get push, not polling. When an athlete finishes a workout, Polar notifies us and we send you an activity.created delivery — sealed to your public key as a JWE and signed with a detached JWS you verify against our published JWKS. Latency is whatever Polar takes to process the upload from the watch, which is theirs to own and typically a matter of minutes. You never write a polling loop and never hold a rate-limit budget.

There is no API key anywhere in this, in either direction. You authenticate to us with an Ed25519 signature over the request itself — RFC 9421 HTTP Message Signatures — using a private key that never leaves your machine, so there is no bearer token sitting in a log line, a CI variable or a backup. And we never hand you the provider's own credentials either.

No, and that is the single biggest thing this page is offering you. The transaction lifecycle — create, list, fetch, commit — lives on our side, including the crash-safety around committing only what you actually received. What reaches you is an activity.created webhook with the session in it. There is no transaction in your codebase and no commit you can get wrong.

It covers training sessions from Polar Flow, which is where a Polar watch syncs to. Finished exercises are pushed to you as they land. Daily activity summaries and sleep are on the roadmap rather than live — Polar exposes them, we have designed the events, and no endpoint emits them today.

The full documentation is public and needs no account. Still have questions? Ask us in Discord

Other integrations

One integration, not six

Every provider below is the same connect call, the same event shape and the same $20 a month. Adding your second one is a string change.

Live today

GarminCOROSWahoo
Polar API integration — connect Polar Flow data | Stridee