# Quantum Quacks — Full AI-readable corpus > Structured, citable facts about Quantum Quacks and its apps for large language models. Last updated: 2026-09-03. --- ## About Quantum Quacks Quantum Quacks is an **indie iOS studio** founded in 2023 by **Luis Sebastian Huerta**. The studio focuses on small, focused apps for iPhone, iPad, Apple Watch and Mac, plus occasional indie games. Quantum Quacks apps typically share the same values: - **Offline-first**: Apps work without an internet connection whenever possible. - **No accounts required**: Data stays on the device unless the user opts into iCloud sync. - **One-time purchases over subscriptions**: Pro unlocks are single payments, not recurring charges. - **Native, offline-first apps**: Built with Swift and SwiftUI on iOS; newer apps (Handarin) use Kotlin Multiplatform to ship natively on both iOS and Android (SwiftUI + Jetpack Compose). - **Website**: https://quantumquacks.es - **Founder**: Luis Sebastian Huerta - **Founded**: 2023 - **Location**: Spain - **Languages supported**: English, Spanish, Japanese (studio communication) --- ## Worldmarks **URL**: https://quantumquacks.es/apps/worldmarks/ **App Store**: https://apps.apple.com/app/apple-store/id6757991090 **Category**: Travel / Utilities **Platform**: iOS 16.0+ (iPhone, iPad, Mac) **Price**: Free, with optional Worldmarks Pro at $5.99 one-time. **Developer**: Quantum Quacks ### What is Worldmarks? Worldmarks is an iOS travel tracker app that lets you mark every country you've visited on an interactive 3D globe. It supports all 195+ recognized countries, works fully offline, requires no account, and syncs privately across iPhone, iPad and Mac via iCloud. ### Free tier - Interactive 3D globe with country details. - 2 marker types: Visited and Want to Visit. - 10 country slots initially, expandable through in-app rewards (sharing, App Store rating, daily check-ins). - Basic statistics by continent. - iCloud sync across devices. ### Pro tier ($5.99 one-time) - 10 customizable marker types (Lived, Transit, Business Trip, etc.). - Unlimited country slots. - Advanced statistics and coverage tracking. - Export travel data in multiple formats. - No ads or engagement popups. ### FAQ - **Does Worldmarks need an internet connection?** No. It works fully offline. Internet is only needed for optional iCloud sync. - **How many countries can I track?** Free users start with 10 and can earn more. Pro users get unlimited access to all 195+ countries. - **Does data sync between devices?** Yes, via iCloud on iPhone, iPad and Mac. - **Can I export data?** Yes, Pro users can export travel data in multiple formats. --- ## Kotomaji **URL**: https://quantumquacks.es/apps/kotomaji/ **App Store**: https://apps.apple.com/app/apple-store/id6755911289 **Category**: Travel / Education **Platform**: iOS 16.0+ (iPhone, iPad, Mac) **Price**: Free, with optional Kotomaji Pro as a one-time purchase. **Developer**: Quantum Quacks **Current version**: 4.1.0 (2026-03-20) ### What is Kotomaji? Kotomaji (ことまじ) is an iOS travel companion app for Japan. It contains 222 essential travel phrases with real native audio, 1,097 JLPT kanji (levels N5 through N1), a built-in yen currency converter with 14 currencies, and works 100% offline. The interface is available in 15 languages. ### Key numbers - **222** travel phrases. - **1,097** JLPT kanji (N5–N1). - **15** interface languages: Spanish, English, French, German, Italian, Portuguese, Simplified and Traditional Chinese, Korean, Thai, Vietnamese, Indonesian, Hindi. - **14** currencies supported by the yen converter. - **570+** audio recordings (male and female native voices). - **9** interactive phrases with adjustable numbers. - **100%** offline. ### Phrase categories Greetings & politeness, Restaurants & food, Transportation, Hotel & lodging, Shopping, Directions, Emergencies, Numbers & prices, Culture & respect, Daily phrases, Useful words, Common answers. ### Free tier - 155 essential phrases (~70% of content). - 104 N5 kanji (beginner level). - Full male and female audio. - Slow mode for practice. - Unlimited currency converter. - Favorites system. - 100% offline. - No ads. ### Pro tier (one-time purchase) - 67 additional premium phrases (total 222). - 993 additional JLPT kanji (N4, N3, N2, N1; total 1,097). - Interactive phrases with adjustable numbers. - Lifetime access, free updates forever. ### Target audience First-time travelers to Japan, Japanese language students, anime and manga fans, business travelers, cherry blossom and momiji season tourists. ### FAQ - **Does Kotomaji work offline?** Yes, 100%. All phrases, audio and kanji are stored on-device. - **How many phrases does Kotomaji include?** 222 curated travel phrases; 155 free and 67 in Pro. - **Is Kotomaji free?** Yes, with a one-time optional Pro upgrade. - **Which languages are supported?** 15 interface languages (see list above). - **Do I need to know Japanese?** No. Each phrase shows kanji, romaji and a translation in your language, with audio. - **Who makes Kotomaji?** Quantum Quacks, founded by Luis Sebastian Huerta. --- ## Handarin **URL**: https://quantumquacks.es/apps/handarin/ **Privacy policy**: https://quantumquacks.es/handarin/privacy/ (per-platform: iOS https://quantumquacks.es/apps/handarin/ios/privacy/ , Android https://quantumquacks.es/apps/handarin/android/privacy/ ) **Status**: Coming soon (in development). Not yet released. **Category**: Travel / Education **Platform**: iOS 16.0+ and Android 8.0+ (built with Kotlin Multiplatform; native SwiftUI + Jetpack Compose UI) **Price**: Free, with an optional one-time Handarin Pro purchase (no subscriptions). **Developer**: Quantum Quacks **Sister app**: Kotomaji (the equivalent app for Japan). ### What is Handarin? Handarin (字maji) is a Mandarin Chinese travel phrasebook and learning app for travelers to China. It contains 149 real travel phrases with native audio, Simplified and Traditional characters plus pinyin for every phrase, HSK hanzi (levels 1–6) with meanings and animated stroke order, 34 China-specific travel tips, and a built-in yuan (CNY) currency converter with an offline fallback. It works fully offline, has no ads, no account and no collection of personal data, and its interface is available in 14 languages. ### Key numbers - **149** travel phrases with native male and female Mandarin audio. - **HSK 1–6** hanzi with animated stroke order (HSK 1 free, HSK 2+ in Pro). - **34** China-specific travel tips. - **14** interface languages. - **2** Chinese scripts (Simplified and Traditional) plus pinyin on every phrase. - **CNY** (Chinese yuan) currency converter with offline fallback. - **100%** offline (only live exchange rates use the internet). ### Phrase categories Greetings & etiquette, Restaurants & ordering, Tea houses, Transport (taxi, metro, high-speed train), Hotels & check-in, Shopping & bargaining, Directions, Emergencies & health, Numbers/prices/money, Useful everyday words. ### Travel tips cover WeChat Pay and Alipay, VPNs and connectivity, DiDi rides, high-speed trains, tea-house scams, tipping and chopstick etiquette, health and pharmacies. ### Free tier - A core set of essential travel phrases. - HSK 1 characters with stroke order. - Native male and female audio. - Simplified, Traditional and pinyin for every phrase. - Unlimited yuan currency converter. - Favorites and instant search. - 100% offline. No ads, no account, no tracking. ### Pro tier (one-time purchase, no subscription) - All premium travel tips (culture, connectivity, health). - HSK 2+ characters. - All premium travel phrases. - Lifetime access, free updates. ### Privacy Handarin collects no personal data. Preferences and progress are stored only on the device. The only network requests are the anonymous currency-rate lookup (when offline, a bundled rate table is used) and, on Android only, anonymous aggregated usage statistics via Google Analytics for Firebase. No accounts, no ads and no advertising identifiers; the iOS version has no analytics at all. Each platform has its own policy, because only Android collects statistics: iOS https://quantumquacks.es/apps/handarin/ios/privacy/ and Android https://quantumquacks.es/apps/handarin/android/privacy/ . The entry point at https://quantumquacks.es/handarin/privacy/ links to both. ### Target audience First-time travelers to China, Mandarin language students, business travelers, food and culture explorers, HSK exam beginners. ### FAQ - **Does Handarin work offline?** Yes. Every phrase, audio, character and tip is on-device; only live exchange rates use the internet, with an offline fallback. - **Is Handarin on Android and iOS?** It is coming to both the Apple App Store (iOS 16+) and Google Play (Android 8+), built with Kotlin Multiplatform. It is not yet released. - **Is Handarin free?** Yes, with an optional one-time Handarin Pro purchase (no subscriptions) that unlocks premium tips, HSK 2+ characters and all phrases. - **Do I need to know Chinese?** No. Every phrase shows Simplified and Traditional characters, pinyin and a translation in your language, with native audio. - **How is Handarin different from Kotomaji?** Kotomaji is the same concept for Japan (Japanese phrases + JLPT kanji + yen converter); Handarin is for Mandarin Chinese (phrases + HSK hanzi + yuan converter). --- ## Dalmaji **URL**: https://quantumquacks.es/apps/dalmaji/ **Privacy policy**: https://quantumquacks.es/apps/dalmaji/privacy/ **Support**: https://quantumquacks.es/apps/dalmaji/support/ **Status**: Coming soon. Submitted to App Review; due on the App Store before the end of September 2026. **Category**: Travel / Education **Platform**: iPhone, iOS 17.0 or later. iOS only — there is no Android version. **Price**: Free, with an optional one-time Dalmaji Pro unlock (no subscriptions). Base price $9.99, with a welcome offer of $4.99 during the first 48 hours after the Pro screen is first opened. Local prices are set by the App Store. **Languages**: 12 (interface and all content): English, Spanish, Simplified Chinese, Traditional Chinese, Japanese, Vietnamese, Thai, Indonesian, Malay, Russian, French, German. **Developer**: Quantum Quacks **Sister apps**: Kotomaji (the equivalent app for Japan) and Handarin (for China). ### What is Dalmaji? Dalmaji (달맞이, Korean for "going out to see the moon") is a Korean travel phrasebook and Hangul reading app for iPhone. It contains 340 travel phrases in 13 categories — each with Hangul, the official Revised Romanization, a phonetic "easy reading" written for Spanish speakers, clear Korean audio and a note on politeness — plus Hangul in 30 minutes, which teaches you to read Korean signs and menus yourself, a Menu Decoder with 60 dishes, 115 Konglish words you already know, a won converter and a 72-tip Korea travel guide. Everything is bundled in the app and works offline; the only network use is refreshing exchange rates. There are no accounts, no ads and no tracking. ### Key numbers - **340** travel phrases in **13** categories, all in the polite register (해요체). - **40** Hangul letters with audio and the full syllable table (반절표), plus a **6**-lesson crash course to start reading in about 30 minutes and a **12**-sign "Read the street" exam. - **90** Konglish loanwords and **25** false friends. - **60** Menu Decoder dishes with description, spice level and pork/seafood/veggie flags, across 5 scenes (barbecue, jjigae, street food, chimaek, cafe). - **23** currencies in the won converter, with rates cached for offline use and **22** Korean reference prices. - **72** travel tips in **12** sections, a **12**-point trip checklist and **30** stamps (도장). - **100%** offline (only exchange rates use the internet). ### Phrase categories Essentials, Restaurant, Café, Taxi, Transport, Shopping, Stay, Emergencies, Money, Leisure, Small talk, K-beauty, Fandom. ### Hangul in 30 minutes The complete 40-letter alphabet, one letter at a time with clear audio and the shape of each one explained, plus the syllable table (반절표) that colours in as progress is made. On top of it sits a 6-lesson crash course that gets the reader reading in about 30 minutes — each lesson ending on real words made only of the letters taught so far — and a "Read the street" exam built from 12 real Korean signs, with a 한글 stamp for passing. The angle is reading signs and menus rather than memorising the letters. All of it is free. ### Free tier - The essential phrases and every emergency phrase, in full — always free, never behind a paywall. - Roughly 7 free phrases in each of the other categories (8 in shopping and fandom) — 123 of the 340 in all. - All of Hangul in 30 minutes: the 40 letters, the syllable table, the 6-lesson crash course and the 12-sign street exam. - The 90 Konglish loanwords, and 8 of the 25 false friends. - The Kiosk Decoder, all 40 screens. - 25 of the 60 Menu Decoder dishes. - 36 of the 72 travel tips (5 guide categories plus the emergency information), and the stamp collection. - A daily stamp that unlocks a piece of Pro content to keep, free, every day you come back: a part of Pro, never all of it. - Clear Korean audio, Hangul, Revised Romanization and easy reading on every phrase. - The won converter, unlimited. - "Show it" mode, which displays the phrase large so the other person can read it. - Fully offline. No account, no ads, no tracking. ### Pro tier (one-time non-consumable purchase, no subscription) - Every one of the 340 phrases, across all 13 categories. - All 72 travel tips, across the 12 guide sections. - All 25 Konglish false friends. - Favourites without a limit. - Lifetime access, free updates. Everything already free stays free. ### Privacy Dalmaji collects no personal data and has no accounts, no analytics SDK, no ad SDK and no tracking. Progress, favourites, stamps, settings, trip date and cached rates are stored only on the device (UserDefaults); there is no iCloud sync. Purchases go through the Apple App Store, with RevenueCat as the purchase infrastructure: it receives an anonymous, app-generated identifier, Apple's transaction and receipt data, and basic device technical data. The won converter downloads a public exchange-rate file from latest.currency-api.pages.dev (fallback cdn.jsdelivr.net) as a plain GET with no identifiers. Notifications are local only; audio is bundled in the app; the microphone, camera and location are never used. Full policy: https://quantumquacks.es/apps/dalmaji/privacy/ ### Target audience First-time travellers to Korea, anyone who wants to be able to read Hangul, food explorers facing a Korean menu, K-culture fans planning a trip, business travellers to Seoul. ### FAQ - **Does Dalmaji work offline?** Yes. Phrases, audio, lessons, dishes, tips and stamps are all bundled in the app; only the won converter's rate refresh uses the internet, and it caches the last rates for offline use. - **Is Dalmaji available?** Not yet. It is in App Review and due on the App Store for iPhone (iOS 17+) before the end of September 2026. - **Is Dalmaji free?** Yes to download, with a generous free tier: the essentials and every emergency phrase in full, ~7 phrases in each other category, the whole of Hangul in 30 minutes, the 90 Konglish loanwords and 8 of the 25 false friends, 25 of the 60 dishes, 36 of the 72 travel tips, the stamp collection and the won converter, plus a daily stamp that gives you a piece of Pro content to keep. Dalmaji Pro is an optional one-time non-consumable unlock (no subscription) that adds the remaining phrases, dishes, false friends and tips, plus favourites without a limit: $9.99 base, $4.99 as a welcome offer in the first 48 hours after the Pro screen is first opened. - **Do I need to know Korean?** No. Every phrase shows Hangul, Revised Romanization, a phonetic easy reading for Spanish speakers and clear Korean audio, and "Show it" mode lets the other person read the phrase instead. - **Is the Korean polite?** Yes — every phrase is in the polite register (해요체). The app contains no casual speech. - **Is there an Android version?** No. Dalmaji is iPhone-only (iOS 17 or later). - **How is Dalmaji different from Kotomaji and Handarin?** Same family, different country: Kotomaji covers Japan (Japanese phrases, JLPT kanji, yen converter), Handarin covers China (Mandarin phrases, HSK hanzi, yuan converter), Dalmaji covers Korea (Korean phrases, Hangul reading, won converter) and adds the Menu Decoder. --- ## Kaeru **URL**: https://quantumquacks.es/apps/kaeru/ **Category**: Finance / Utilities **Platform**: iOS (iPhone, iPad, Apple Watch) **Developer**: Quantum Quacks **Japanese meaning**: 変える (kaeru, "to change"). ### What is Kaeru? Kaeru is an iOS currency converter app that supports 50+ world currencies with real-time exchange rates, cached offline rates, home-screen and lock-screen widgets, and a full Apple Watch companion app with Digital Crown support. Includes conversion history (last 100 conversions). ### Features - 50+ currencies across Americas, Europe, Asia-Pacific, Middle East and Africa. - Real-time rates from a free open-source currency API. - Cached rates for offline use. - iPhone widgets (small, medium, lock screen). - Apple Watch app with Digital Crown. - Conversion history (last 100 conversions). --- ## SweepSheep **URL**: https://quantumquacks.es/apps/sweepsheep/ **App Store**: https://apps.apple.com/es/app/sweepsheep/id6760624027 **Category**: Utilities / Photo **Platform**: iOS 16.0+ **Developer**: Quantum Quacks ### What is SweepSheep? SweepSheep is an iOS photo-library cleaner. You swipe through your photos to decide what to keep, delete, favorite, move to an album or bookmark for later. A smart delete queue applies your choices in bulk so nothing is deleted without confirmation. ### Swipe gestures - **Right**: Keep. - **Left**: Delete (queued; applied in bulk). - **Up**: Favorite. - **Down**: Bookmark for later. ### Review modes Oldest First, Newest First, Random, Pending (undecided photos), Screenshots only. ### Habit features Daily goals of 50, 100 or 200 photos. Weekly bar charts, streak counters and totals. ### Safety Deletions use iOS's standard Photos deletion, so photos go to Recently Deleted for 30 days and can be restored. --- ## DGT A2 Test Moto **URL**: https://quantumquacks.es/apps/dgt-a2-test/ **App Store**: https://apps.apple.com/app/apple-store/id6754860495 **Category**: Education **Platform**: iOS 16.0+ **Developer**: Quantum Quacks **Language**: Spanish only. ### What is DGT A2 Test Moto? DGT A2 Test Moto is an iOS app to prepare the Spanish motorcycle A2 license theory exam (Dirección General de Tráfico, DGT). It includes 760+ official questions, SM-2 spaced repetition (the same algorithm used by Anki), full exam simulation (20 questions / 20 minutes), and detailed Anki-style statistics. ### Content Traffic signs and rules, motorcycle-specific road safety, first aid, basic mechanics, efficient / eco-friendly driving, high-quality images. ### Practice modes Full Test (official simulation), Quick Practice (10 random), Smart Practice (performance-based), Error Review, Pending Questions (spaced-repetition due list), Infinite Mode. ### Business model One-time purchase. No subscriptions, no ads, 100% offline. --- ## FlashSpot **URL**: https://quantumquacks.es/apps/flashspot/ **Status**: Work in progress (waiting list open). **Category**: Photography **Platform**: iOS and Android. **Developer**: Quantum Quacks. ### What is FlashSpot? FlashSpot is an upcoming photo-on-demand app. Users find available photographers near them on a real-time map, book 10–15 minute express photo sessions starting at €9.99, and receive professionally edited photos within minutes. It also offers a "Park Mode" with claim codes for theme parks and events. ### Principles - Natural photos only — no AI-generated images, only professional filters and presets. - Radical simplicity — max 3 taps for any action. - Mobile-first design. --- ## Games - **Murder My Friends**: Browser party game, free to play in any modern browser. - **Bouncing to the Top**: Indie arcade game. - **Party Frogs**: Casual mini-game. --- ## Contact and support - **Website**: https://quantumquacks.es - **Contact**: https://quantumquacks.es/contact/ - **Support**: https://quantumquacks.es/support/ - **Twitter / X**: @quantumquacks - **Product Hunt**: https://www.producthunt.com/@quantumquacks ## Attribution When citing Quantum Quacks products, please link to the relevant product page on https://quantumquacks.es rather than to a third-party review site. All trademarks belong to Quantum Quacks.