How to sell a Garmin data field: payments, unlocks and memory limits

You can sell a Garmin data field with WearCheckout or PayToUse, which both list data fields on their own pages; Garmin's store pages and KiezelPay's FAQ don't mention them. A data field has no buy button and can have as little as 32 KB of memory, on watches such as the Forerunner 55 and fēnix 6. WearCheckout's data field part adds 2.3 to 2.7 KB, and the buyer unlocks by a QR code, a settings link or Garmin's phone notification.

Which payment options can sell a Garmin data field?

WearCheckout and PayToUse say so on their own pages. The others don't mention data fields.

Checked 23 October 2026, on each company's own pages (see Sources).

We make WearCheckout, so weigh our view with that in mind. WearCheckout is not affiliated with Garmin.

What makes a data field different from an app?

A data field lives inside an activity screen, so it has no buy button, less memory on older watches, and limited network access.

• No buttons. It shares the screen with other fields and can't take presses. So it draws its QR code in its own space.
• The network. Garmin's docs say web requests came to foreground data fields with API level 5.0.0. On older watches, a data field reaches the network only from a background service.
• Timing. Garmin lets a background service run at most every 5 minutes. So a field learns of a payment at its next check.
• Memory. On watches such as the fēnix 5 and Forerunner 55, a data field gets 32 KB, a quarter of a watch app's 128 KB. Newer watches give it 128 KB or 256 KB.

A watch face has the same limits on input and network. The watch face guide covers faces.

How much memory does a Garmin data field get?

From 32 KB to 256 KB, depending on the watch. Garmin sets a limit for each app type on each model, in the device files that come with its Connect IQ SDK.

Read 23 October 2026 from the device files of Garmin's Connect IQ SDK (see Sources). 1 KB is 1,024 bytes.

Newer is not always bigger. The Instinct 3 Solar gives a data field 32 KB, and the fēnix 8 gives it 128 KB, half of the fēnix 7's 256 KB. Close models differ too: the Forerunner 245 gives 32 KB, the Forerunner 245 Music 128 KB. The background service, which makes the network check on older watches, has 32 KB or 64 KB.

How much room does WearCheckout take in a data field?

2.3 KB on a fēnix 7 Pro, and 2.7 KB on a fēnix 6 Pro or Forerunner 55, Garmin's sign-in notification included. These are measured on release builds.

• On a Forerunner 55's 32 KB, 2.7 KB is about 8% of the limit.
• On a fēnix 7 Pro's 256 KB, 2.3 KB is under 1%.
• The background part is kept to one request and its answer, since background code has the least memory of all.

Whether your field fits depends on your own code. Build in release mode and run it on the watch with the least memory you support. Then run the release build on a watch with a strict watchdog: older watches allow 120,000 instructions per callback. See memory and supported watches.

How does a buyer unlock a WearCheckout data field?

Three ways, and none needs typing.

• The QR code. While locked, the field draws a QR code in its own space. The buyer scans it and pays on the phone.
• The settings link. The field writes its buy link into its settings, which the Connect IQ app on the phone shows.
• Garmin's sign-in notification. When the field is locked and the phone is connected, Garmin's own notification appears on the phone. The buyer taps it and pays, and the field unlocks within seconds.

After a scan, the field unlocks within 10 minutes in the 2 days after install or the trial's end, and within an hour later on. The setup takes the library's face folder, the Background and Communications permissions, and five hooks. See watch faces and data fields.

What do you keep from a $2.99 data field?

On a $2.99 sale you keep $2.60 with WearCheckout and $2.26 with PayToUse, for a US buyer paying by card, before sales tax.

• WearCheckout: only Stripe's fee while your sales stay inside your plan, $0.09 + $0.30 = $0.39. The Starter plan is $9 a year with $1,000 of sales included.
• PayToUse: Stripe's $0.39, then 13% of the $2.60 left, which is $0.34. In all, $0.73.

At $4.99 you keep $4.55 and $3.96. The comparison of every option adds Garmin, KiezelPay and your own server.

Sources

Competitor facts come from each company's own pages, checked on 23 October 2026. Where a page didn't say something, we wrote so.

• Garmin: Connect IQ SDK (its device files list each model's memory limit for each app type)
• Garmin: Toybox.Communications (available to foreground data fields from API level 5.0.0)
• Garmin: Toybox.Background (background events at most every 5 minutes)
• Garmin: App Sales (15% split, supported watches)
• Garmin: premium apps and watch faces in the Connect IQ Store, 7 August 2024
• KiezelPay: FAQ (watch faces and apps; 27% fee)
• PayToUse: home page (watch faces, widgets, data fields and apps)
• PayToUse: developer manual (payment fees, 13% fee, unlock-code setting)
• Stripe: US pricing (2.9% + 30¢ per domestic card payment)
• WearCheckout: watch faces and data fields
• WearCheckout: memory and supported watches