Scan your greeting cards, then open and close them in 3D by opening and closing the Duo
Does Kaartje work on iPhone Duo?
Yes, says the developer: on iPhone Duo the scanned cards open and close in 3D as you open and close the phone.
- Developer claimedLuuk van Baars, the developer, in a submission to FoldHunt on October 24, 2026, ticking the closed, open and Split View poses. The App Store seller is Luuk van Baars. The release notes for version 1.1.1 (released October 23, 2026) say cards that fold at the top now line up with the Duo's fold too.
Adapted for the fold
- Open · Inner display
The card follows the hinge
Open and close the phone and the scanned card opens and closes with it, in 3D. Cards that fold at the top line up with the fold too.
About Kaartje
Kaartje, Dutch for “little card”, is an app by Luuk van Baars for the box of greeting cards everyone keeps somewhere. Scan a card, front and inside, and it opens on the phone like the real thing, folding out in 3D with the handwriting in place. Turn it over to read the back, search by sender, occasion or the words inside, and gather cards into moments such as a wedding or a birthday.
On iPhone Duo, the developer says, the cards open and close as you open and close the phone. Version 1.1.1 lines up cards that fold at the top with the Duo’s fold as well.
Related guides
The best iPhone Duo apps so far (October 2026)
The apps worth installing now that iPhone Duo is on sale, from the apps Apple named as launch partners to indie apps whose developers have shown a real iPhone Duo layout, picked for what they do when you open the phone.
Do your apps work on iPhone Duo? What happens before they're updated
Every iPhone app opens on iPhone Duo, but only updated ones fill the inner display. What an app looks like before its developer adapts it, how to tell which are ready, and which popular apps have said so.
Is this your app?
Add the badge to your site or press kit. It links back to this page, where fans can upvote you.
<a href="https://foldhunt.com/apps/kaartje/"><img src="https://foldhunt.com/badges/featured-on-foldhunt.svg" alt="Featured on FoldHunt" width="220" height="54"></a>Need to update the listing? Email the editor.
More for iPhone Duo
KeepCount
Tyler Hillsman / 1881 Digital, LLC
A board of tally counters: half-folded, counts sit above the fold and the buttons below
Simulator verified: Tyler Hillsman, the developer, in a submission to FoldHunt on October 17, 2026, with an unframed screenshot of the app in the iPhone Duo simulator in the press kit (keepcount.app). The App Store seller is 1881 Digital, LLC. The release notes for version 1.8 (released October 12, 2026) say KeepCount now adapts to the iPhone Duo's inner and outer displays, with a tabletop layout when it's partly folded.
- Book
- Closed
- Open
Calc Pro - The Best Calculator
Panoramic Software Inc.
Ten calculators and converters, with the tape of results beside the calculator when open
Simulator verified: Panoramic Software Inc., the developer, in a submission to FoldHunt on October 18, 2026, and in the App Store release notes for version 7.0.6 (released October 12, 2026), which describe the closed and open layouts. The app's page on the developer's website has pictures of both on the iPhone Duo.
- Closed
- Open
Sticky Widgets
Tyler Hillsman / 1881 Digital, LLC
Sticky notes as widgets, with a larger library and side-by-side editing on the Duo
Simulator verified: Tyler Hillsman, the developer, in the App Store release notes for version 5.4.0 (released October 13, 2026), which add iPhone Duo support with a larger library and side-by-side editing, and in a submission to FoldHunt on October 17, 2026, with an unframed screenshot of the app in the iPhone Duo simulator in the press kit (stickywidgets.app). The App Store seller is 1881 Digital, LLC; the App Store pictures show ordinary iPhones and iPads.
- Open