# [001] A one-time-purchase iPhone app for Duo that makes the opening and closing itself the gameplay (toys, retro devices, utilities), $3–5 one-time

> Source: https://stringers.io/en/o/001.html (Stringers / 什么值得做, generated 2026-11-08)
> Stringers answers one question every day: what small product can one or two people build in a few months and actually make money from. Numbers come from 15 databases we collect daily, each with source and date.
> For agents: these verdicts and the underlying databases (verified revenue, App Store / Google Play charts, ad libraries, GitHub, Product Hunt…) are queryable live over MCP — tools today / hot / products / directions / direction / data. Setup: https://github.com/komako-workshop/stringers (the user logs in at stringers.io → "配置 agent" to get a personal URL). Site index: https://stringers.io/llms.txt

> Small install base (about 500–7M units this year), but these owners are the ones most willing to pay for novel mechanics, and big devs are busy with "big-screen adaptation" and nobody has built a "fold-to-interact" toy yet

[Home](https://stringers.io/worth/) / [001]

# One-time paid small app for iPhone Duo that makes opening and closing the gameplay itself (toys, retro devices, tools), $3–5 one-time purchase

Open Trackable · new hardware window First spotted 2026-10-31 · last updated 2026-11-08

Status

Open (US cooling slowly; 28 countries that opened sales 10-30 are the second wave)

Why now, and how long the window lasts

The install base is small (about 500–7M units this year), but these owners are the most willing to pay for novel features, big developers are only focused on "large-screen adaptation," and nobody has built a toy where "opening and closing is the interaction." The novelty usually lasts 4–8 weeks; the 10-30 launch of 28 countries/regions and the year-end gift season are the second wave. The window is estimated to end in December 2026, and the US is already declining.

Confidence

Medium-high. Rankings are hard data; revenue isn't available (Apple doesn't disclose downloads, and rating counts are small: Toastie has 92 US ratings). Would be disproven if: all such apps drop out of the US paid top 50 before 11-15; a hinge crack escalates into a recall or discontinuation; or Apple releases a similar toy itself.

## Evidence

Grouped by store. Each group starts with the charts that can be graphed (real curves, data dates below the chart), then the scanner's original notes and source links.

### App Store4 evidence items · 9 products with curves

[Toastie: grilled cheese game](https://apps.apple.com/us/app/toastie-grilled-cheese-game/id6813841355) Tomasz Szykulski

App Store · Launched 2026-10-09 · US store rating 158 · 11-08 Best overall Top Paid rank #3 (Qatar) · 11-08 Charted in 86 stores

Top Paid chart rank · by store

US store Germany France

Data 2026-10-28 → 2026-11-08 (12 days, 12 observations). Lower rank is higher; gaps mean it wasn't charted that day

Stores where it made the overall chart (top 200 on any chart)

Data 2026-10-28 → 2026-11-08 (12 days, 12 observations)

[Tiny Computers](https://apps.apple.com/us/app/tiny-computers/id6816896250) Fountain Interactive Ltd

App Store · launched 2026-10-23 · US store rating 64 · 11-08 best overall Top Paid rank #3 (UAE) · 11-08 charted across 78 stores

Top Paid chart rank · by store

US store Germany Australia

Data 2026-10-28 → 2026-11-08 (12 days, 12 observations). Lower rank is higher; gaps mean it wasn't charted that day

Stores where it made the overall chart (top 200 on any chart)

Data 2026-10-28 → 2026-11-08 (12 days, 12 observations)

[Deck-Man: Cassette Player](https://apps.apple.com/us/app/deck-man-cassette-player/id6817070335) Squircle Apps LLP

App Store · launched 2026-10-14 · US store rating 193 · 11-08 best overall Top Paid rank #4(BH) · charted in 11-08 74 stores

Top Paid chart rank · by store

US store France Germany

Data 2026-10-28 → 2026-11-08 (12 days, 12 observations). Lower rank is higher; gaps mean it wasn't charted that day

Stores where it made the overall chart (top 200 on any chart)

Data 2026-10-28 → 2026-11-08 (12 days, 12 observations)

[TypeDraw](https://apps.apple.com/us/app/typedraw/id6822194774) Trautmann & Dorre GbR Shaped Agency

App Store · launched 2026-10-20 · US store rating 70 · 11-08 best overall Top Paid rank #5 (UAE) · 11-08 charted across 77 stores

Top Paid chart rank · by store

US store Germany Spain

Data 2026-10-28 → 2026-11-08 (12 days, 12 observations). Lower rank is higher; gaps mean it wasn't charted that day

Stores where it made the overall chart (top 200 on any chart)

Data 2026-10-28 → 2026-11-08 (12 days, 12 observations)

[Orisuji](https://apps.apple.com/us/app/orisuji/id6817092898) Adrien Friggeri

App Store · launched 2026-10-23 · US store rating 14 · 11-08 best overall Top Paid rank #126 (SK) · charted in 11-08 19 stores

Top Paid chart rank · by store

US store CY BG

Data 2026-10-28 → 2026-11-07 (11 days, 11 observations). Lower rank is higher; gaps mean it wasn't charted that day

Stores where it made the overall chart (top 200 on any chart)

Data 2026-10-28 → 2026-11-08 (12 days, 12 observations)

[Flipcorder: Retro Camcorder](https://apps.apple.com/us/app/flipcorder-retro-camcorder/id6818168418) Lotus Apps, LLC

App Store · launched 2026-10-23 · US store rating 21 · 11-08 best overall Top Paid rank #21 (Colombia) · charted in 11-08 39 stores · [View product profile](https://stringers.io/worth/p/flipcorder.html)

Top Paid chart rank · by store

US store Colombia PY

Data 2026-10-28 → 2026-11-08 (12 days, 12 observations). Lower rank is higher; gaps mean it wasn't charted that day

Stores where it made the overall chart (top 200 on any chart)

Data 2026-10-28 → 2026-11-08 (12 days, 12 observations)

[Chromagraph Camera](https://apps.apple.com/us/app/chromagraph-camera/id6803329435) Chromatic Applications LLC

App Store · launched 2026-10-20 · US store rating 192 · 11-08 best Top Paid overall rank #1 (CY) · charted in 11-08 stores 99

Top Paid chart rank · by store

US store Canada Spain

Data 2026-10-29 → 2026-11-08 (11 days, 11 observations). Lower rank is higher; gaps mean it wasn't charted that day

Stores where it made the overall chart (top 200 on any chart)

Data 2026-10-29 → 2026-11-08 (11 days, 11 observations)

[Wider - Fullscreen Browsing](https://apps.apple.com/us/app/wider-fullscreen-browsing/id6824686276) Jordi Bruin

App Store · Launched 2026-10-29 · US rating 35 · 11-02 best overall Top Paid rank: #6 (Oman) · charted 11-02 in 53 stores

Top Paid chart rank · by store

US store Canada France

Data 2026-11-01 → 2026-11-02 (2 days, 2 observations). Lower rank is higher; gaps mean it wasn't charted that day

Stores where it made the overall chart (top 200 on any chart)

Data 2026-10-31 → 2026-11-02 (3 days, 3 observations)

**1 more products' curves**

[Wide Web: Full Screen Safari](https://apps.apple.com/us/app/wide-web-full-screen-safari/id6818616702) ZooKeeper Media LLC

App Store · Launched 2026-10-22 · US store rating 11 · 11-08 · Best overall Top Paid rank #147 (Italy) · 11-08 charted across 7 stores

Top Paid chart rank · by store

Korea Italy UK

Data 2026-10-31 → 2026-11-08 (9 days, 7 observations). Lower rank is higher; gaps mean it wasn't charted that day

- App Store, all stores (2026-10-31): a total of 4,763 apps mention "[iPhone Duo](https://stringers.io/worth/p/apple.html)" in their description or update notes; the earliest version date is 2026-09-11. Looking only at solo or small-developer apps first released after September, the top of the multi-store paid charts includes:
    - Toastie (id 6813841355, Tomasz Szykulski, launched 10-09, $2.99): #13 on the US store Top Paid overall chart, gb #23, de #24, fr #12, au #15; charted in 78 stores total; as_app shows US store rating 4.83★ from 92 ratings. Gameplay: closing Duo is like shutting a toaster lid. [apps.apple.com/us/app/toastie-grilled-cheese-game/id68138413…](https://apps.apple.com/us/app/toastie-grilled-cheese-game/id6813841355)
    - Tiny Computers(6816896250, Fountain Interactive, launched 10-23, $3.99): US Top Paid #15, DE #12, CA #15, AU #18, JP #46; US store rating 3.60★ from 20 ratings. Folds Duo into desktop mode: top screen is a retro computer display, bottom screen is a keyboard. 10 retro computers in total.
    - Deck-Man: Cassette Player(6817070335, Squircle Apps, launched 10-14, $4.99): #16 on US Top Paid, #34 in gb store, #46 in de store, 117 US ratings; Apple's 10-22 newsroom post named it.
    - TypeDraw (launched 6822194774,10-20, $4.99): US Top Paid #20, de #15, gb #27.
    - Tier 2: Orisuji (6817092898, #96 US Top Paid, #3 US Photo / Games category Top Paid), [Flipcorder](https://stringers.io/worth/p/flipcorder.html) retro camera (6818168418, #12 US category Top Paid), Fold Accordion, Foldometer (measures fold angle, $0.99). Free ones: PianoFold (#9 US category Top Free), Battlefleet Duo.
    - Chromagraph Camera(6803329435,$12.99) ranked #1 on the US store and gb Top Paid overall chart, but it runs on the name of Steve Yedlin, the cinematographer behind Knives Out. Small teams can't copy that. It only shows that a camera app at $13 can sell.

- Ranking trend (App Store, US overall Top Paid, 10-28 → 10-31): Tiny Computers 7→8→14→15, Toastie 9→9→11→13, Deck-Man 11→10→?→16. Number of apps in the US Top 100 Paid that were first released after September and whose text mentions Duo / fold / hinge: 10-28 has 5, 10-29 has 7, 10-30 has 5, 10-31 has 6; in GB the count rose from 4 to 6, in JP from 6 to 7. (This count comes from a keyword screen and may include a few false positives.)

- Tools that fix Duo's rough edges (11-01 new): Wider - Fullscreen Browsing (id 6824686276, Good Snooze, launched 10-29, $2.99, Safari extension, makes web pages use the full width of Duo's outer screen): 11-01 overall Top Paid us #8, ca #6, fr #7, gb #11, de #14, au #12; US store ratings: 10, 4.0★. Similar Wide Web: Full Screen Safari (launched 6818616702,10-22) only reached au #92, ca #105. The pain point matches what TrendForce calls "black bars on apps, poor adaptation," and what Max Weinbach 10-21 describes: "when I got my Duo, only 3 apps supported it." How long these tools last depends on how fast big apps adapt (inference: probably a few months).

- App Store (all stores, 11-02): control Chromagraph (6803329435) still #1 on the US Top Paid overall chart, but the stores where it charts in Top Grossing dropped from 24 at report time to 9. Qualifying list 11-02: "flat" (two-day score +181).

### Product Hunt1 pieces of evidence

- PH (PT date): [Flipcorder](https://stringers.io/worth/p/flipcorder.html) 10-26 #7 of the day, 129 points; Penta, a 90s 5-disc CD changer10-24 #8, 101 points; Headroom, a Mac remote that folds out into a keyboard10-23 #16, 83 points. Other smaller launches include Carriage (typewriter), Luminette (1927-style box camera), DawnDuo (sunrise alarm clock) and Stress Less, all with fewer than 10 votes.

### Other sources (official sites, press releases, web pages) 1 pieces of evidence

- Apple newsroom (2026-10-22): [www.apple.com/newsroom/2026/10/developers-bring-incredible-n…](https://www.apple.com/newsroom/2026/10/developers-bring-incredible-new-app-experiences-to-iphone-duo/). The iOS 27.1 SDK adds a hinge angle API and a cross-crease layout API. Deck-Man is named among indie devs.

### deeply 1 pieces of evidence

- Shipments (deeply): TrendForce estimates 2026 Duo shipments at about 5M units (2026-10-28, relayed by IT Home); IDC about 7M; in July, Ming-Chi Kuo judged 2H26 at about 700–8M units, with real demand clear only by late 2026 to Q1 2027. Lead times in the launch week were pushed to January 2027.

### X1 pieces of evidence

- X (local library): Max Weinbach 10-21 said "when I got the Duo, only 3 apps supported it"; Marc Lou 10-23 and 10-30 both called the Duo a flop (❤3,224); 10-26 a Korean display-industry reporter reported cracking in the hinge area (relayed by @jukan05).

### Indie product revenue (TrustMRR)1 evidence · 1 products with curves

[Store Stock Checker](https://trustmrr.com/startup/store-stock-checker) storestockchecker.com

TrustMRR · 30-day revenue $29,252 (+0%) · MRR $29,236 · 3,829 subscriptions

Monthly revenue (verified by payment platform)

2026-10 → 2026-11 (2 pts). Light bars = current month, not yet complete

Daily revenue (UTC day)

Data 2026-09-29 → 2026-11-06 (39 days, 39 observations). Single-day swings are big, so look at the trend in the monthly breakdown above.

- indie (US, 11-01-core, merch spun off from Duo): Store Stock Checker (storestockchecker.com, tracks [iPhone Duo](https://stringers.io/worth/p/apple.html) in-store stock at Apple Stores, $5 / 10 / 20 per month) first revenue on 10-23, $22,465 in 30 days, 2,940 subscriptions, daily revenue peaked at $4,955 on 10-28, then fell back to $2.3–2.6k a day. The Duo shortage also spawned a small business, filed under [037](restock alerts).

## Already doing it

Of the top 8–10 above, each takes one concrete metaphor (toaster, retro computer, tape deck, CD changer, typewriter, camcorder, accordion, protractor, paper maze). Metaphors still open (inferred, not checked one by one): flip phone / pager nostalgia, makeup mirror / compact case, book-style readers (spine crease), instruments (beyond accordion), board game boards, Game & Watch-style dual-screen handhelds.

In our product archive: [Flipcorder](https://stringers.io/worth/p/flipcorder.html), [iPhone Duo](https://stringers.io/worth/p/apple.html)

## The hardest step

Creativity and polish, not tech. It has to run on a regular iPhone too (Tiny Computers fakes perspective on a regular iPhone and shows the whole computer on an iPad), or the only buyers you can reach are the few million Duo owners. The one-time purchase price also means you only catch the launch wave.

## Who it's for

iOS / SwiftUI indie devs who can ship a polished small app in 2–3 weeks; one-time purchase at $2.99–4.99; one person is enough; mainly the US store, with some Japan and Germany demand.

## Should every product builder know this?

Yes. "New hardware form factor + a solo-built one-time purchase toy hitting the Top Paid overall chart" is a repeatable pattern. The next one could be a touchscreen Mac ([006]) or some other new device.

## Change log

2026-11-08

US Top Paid overall: Tiny Computers 7, Deck-Man 13, TypeDraw 18, Toastie 21. Stores where each is in the top 50 paid: Tiny 37, Toastie 36, Deck-Man 23 (up from 14), TypeDraw 17. In the third weekend after launch, all four are still in the top 25 in the US, more durable than our earlier call that it would shrink by the end of 11-03. Keep open.

2026-11-07

US Top Paid overall chart: Tiny Computers #8, Toastie #22→#18, Deck-Man #16→#14, TypeDraw #25→#19; stores charted in Top Paid top 50: Tiny 37→34, Toastie 34→39, TypeDraw 18→17, Deck-Man 11→14. Over the weekend, all four are still in US top 20; store count stopped falling and stayed flat. No change.

2026-11-06

US Top Paid overall: Tiny Computers 8→10, Toastie 22→23, Deck-Man 16→22, TypeDraw 25→19. Stores in the top 50 of Top Paid: Tiny 40→37, Toastie 43→34, TypeDraw 23→18, Deck-Man 15→11. US rank is holding, but store count dropped about 40% in a week (Toastie is at 60 stores, 10-28 before). The second wave is mostly over. Keep it open, window estimated to end around November. If 11-15 US Top Paid top 50 is down to 1 or fewer, change to Narrowing.

2026-11-05

US store Top Paid overall chart: Tiny Computers 15→10, TypeDraw 18→19, Toastie 24→23, Deck-Man 22→22; stores charting in Top Paid top 50: Tiny 44→40, Toastie 47→43, TypeDraw 26→23, Deck-Man 16→15. US ranks holding steady, store count slowly shrinking. Unchanged.

2026-11-04

US overall Top Paid: Tiny Computers 11→15, TypeDraw 17→18, Toastie 23→24, Deck-Man 22→22. Stores in the top 50 Paid: Tiny 43→44, Toastie 46→47, TypeDraw 35→26, Deck-Man 20→16. Toy apps are holding between ranks 15–25 in the US, not a cliff; TypeDraw is falling fastest. Status unchanged, window still estimated at the end of November.

2026-11-03

US overall Top Paid: Toastie 18→23, Tiny Computers 10→11, TypeDraw 12→17, Deck-Man 20→22. Stores in the top 50 Paid: Tiny 54→43, Toastie 49→46, TypeDraw 40→35, Deck-Man 25→20, and Wider has dropped out of the top 50 in every store. The weekend's second wave lasted two days before the whole thing fell back; judging that the US novelty has passed its peak, with the rest depending on new-store launches and the year-end. Accessories driven by the Duo shortage are in [037]: Store Stock Checker subscription 3,185. Status unchanged (still running); window estimated to shrink to the end of November.

2026-11-02

Backfill (from "App Store New Opportunities" §1.7): Chromagraph overall Top Grossing 24 store → 9 store, Top Paid overall us #1 unchanged. Split out as [032] (camera aesthetics, one-time purchase). Store Stock Checker, surfaced from Duo's out-of-stock issue, goes under [037].

2026-11-02

No more drops over the weekend: US Top Paid Tiny Computers 13→10, TypeDraw 10→12, Toastie 18→18, Deck-Man 17→20; UK Toastie 23→13. Stores charted in Top Paid top 50: Tiny Computers 45→54, Toastie 50→49, TypeDraw 40→40. The fix-it tool Wider is falling fast (US 8→21, stores in top 50 36→23), so heat for this kind of tool runs shorter than for toys. New entries: Game & Duo: Retro LCD Games (10-31, $2.99, UK category 43) and Midnight Fridge (10-31, $2.99, UK category 14). Both ranks are low. Status unchanged: still open.

2026-11-01

US store: Toastie 13→18, Tiny Computers 15→13, Deck-Man 16→17, TypeDraw 20→10 (rebounding). The number of stores charting in the overall Top Paid top 50 has stopped falling and is climbing back: Toastie 44→50, TypeDraw 22→40, Tiny Computers 41→45. This is likely the newly launched 28 store (on 10-30) driving a second wave. A new sub-opportunity has appeared: fixing Duo's flaws. Wider (launched 10-29, $2.99) is #8 on the US Top Paid chart, and Wide Web (10-22) is doing the same thing (see evidence). Status unchanged: still open.

2026-10-31

First time on record. The US store Top Paid top 20 has 4 of them: Toastie 13, Tiny Computers 15, Deck-Man 16, TypeDraw 20, slowly sliding since 10-28.

Original: Scanner opportunity library #001 (updated daily, 06:00); this page was generated on the 2026-11-08 edition.