Boilerplate, facts and figures, founder bio, logos, screenshots, open datasets, and the press contact, in one place. Everything here is free to quote and publish.
LearnClash is a competitive learning app for teens and adults, 13 and up. Players take on 1v1 quiz duels on any topic, from quantum physics to pop culture, and are matched by skill with a Glicko-2 rating shown as an ELO number across 8 tiers from Iron to Phoenix. Every question a player sees enters a built-in 3-stage spaced-repetition cycle, returning after 7 days and again after 90, so duels turn into knowledge that sticks. LearnClash is free on iOS and Android in English, German, French, and Spanish, with no ads in any tier and no ad-network SDKs in the app; Premium subscriptions are the only revenue. It is built and operated by Pluxia GmbH in Baar, Switzerland, founded by David Moosmann, and has been live since September 2025.
Short version: LearnClash is a competitive learning app where 1v1 quiz duels on any topic feed a 3-stage spaced-repetition system. Free on iOS and Android, no ads, built by Pluxia GmbH in Baar, Switzerland.
Design constants can be checked in the live app. Dated figures come from read-only exports of the LearnClash production database and carry their extraction date. The long-form write-ups are LearnClash by the numbers and the Misconception Index.
| What it is | A competitive learning app: 1v1 quiz duels on any topic, with built-in spaced repetition so players retain what they learn. |
|---|---|
| Live since | September 2025 (LearnClash 1.0 on iOS and Android) |
| Platforms and languages | iOS and Android; English, German, French, and Spanish |
| Minimum age | 13 and up |
| Store category | App Store: Education (primary), Games > Trivia (secondary). Google Play: Games > Trivia |
| Pricing | Free tier with daily duels, all topics, and ELO ranking. Premium: $7.99 per month or $59.99 per year, with a 7-day free trial on the annual plan. |
| Ads | No ads in any tier and no ad-network SDKs in the app. Premium subscriptions are the only revenue. |
| Duel format | 18 questions per duel: 6 rounds of 3, with 45 seconds per question. One turn is 6 questions, about 3 minutes. |
|---|---|
| Turn window | Asynchronous, 72 hours per turn, 3 turns per player |
| Solo session | 6 questions |
| Rating engine | Glicko-2 underneath, shown as a familiar ELO number. Every player starts at 1300 (Gold II). New players calibrate in about 10 duels. |
| Ladder | 8 tiers and 22 ranks, from Iron (100-599) to Phoenix (2400+) |
| Matchmaking | Weighted composite of 50 percent ELO proximity and 50 percent category similarity, with no hard rating gate |
| Spaced repetition | 3 stages. A missed question returns in 7 days; pass that and it returns in 90 days; pass that and it exits the active pool. A wrong answer drops one stage, never the full chain. |
| Question catalog | 34,157 questions across 655 topics (production export, July 21, 2026). Median topic: 27 questions; deepest topic: General Knowledge at 512. |
|---|---|
| Catalog growth | From 28,891 questions across 570 topics (June 9, 2026) to 34,157 across 655 (July 21, 2026): up 18 percent in six weeks |
| Trivia Difficulty Index | June 2026: 80,553 real answers, 156 ranked topics, 43.5 percent of answers wrong overall. July 21, 2026 re-run: 116,783 answers, 187 ranked topics, 43.7 percent. |
| Hardest and easiest topics | Culture (61.5 percent wrong), Law (61.1), Art (59.9). Easiest ranked topic: German Proverbs at 6.3 percent. |
| Misconception Index | July 27, 2026 export: 39,113 questions scanned, 24,065 with first-encounter duel answers, 267 rows publishable. Headline row: 56.2 percent said the early samurai's primary weapon was a curved longsword; 21.9 percent picked the bow. |
| Company | Pluxia GmbH, Blegistrasse 7, 6340 Baar, Zug, Switzerland |
|---|---|
| Founded | December 1, 2023 (Canton of Zug) |
| Commercial register | UID CHE-198.527.946 |
| Founder | David Moosmann, founder and sole developer of LearnClash, director of Pluxia GmbH |
| Stack | Flutter with signals.dart on the client; Firebase Cloud Functions and Firestore on the backend |
| Wikidata | App Q138771266, founder Q138771338, company Q140154726 |
David Moosmann is the founder and sole developer of LearnClash and the director of Pluxia GmbH in Baar, Zug, Switzerland. Born in Tübingen, Germany, he builds LearnClash end to end: product design, the Flutter mobile app, the Firebase backend, marketing, and every article on the LearnClash blog. He shipped LearnClash 1.0 on iOS and Android in September 2025.
Full bio and contact links: About David Moosmann. Wikidata: Q138771338.
Around 2012 David and his mother got hooked on QuizDuel and played daily for 12 years, around 18,000 rounds at breakfast, on commutes, and late in the evening. By 2024 the awkward part was clear: she still missed the same Saturn-moon question, he still missed the same Hungarian river. The duels were fun, the streaks were satisfying, and the learning was close to zero. Quiz games test what you already know; they do not teach.
The wedge was simple: keep the 1v1 duel mechanic that held them for 12 years, layer real spaced repetition into every mode, and use a rating so matches stay balanced rather than random. Prototyping started in April 2024, with the first working duel screen. LearnClash 1.0 shipped on iOS and Android in September 2025. The full story is on the founder page.
LearnClash publishes two datasets from its production database under CC BY 4.0. Both hold aggregates only, never user-level records.
A league table of real per-topic wrong rates: 570 topics, answer-weighted wrong rates from 80,553 real answers, 156 topics clearing the ranking thresholds. Refreshed quarterly; the next Kaggle update lands in September 2026.
Cite as: "LearnClash Trivia Difficulty Index, June 2026, Pluxia GmbH (learnclash.com)".
Which specific wrong answer people pick, and how often. One row per question with at least 30 first-encounter duel answers, the most-picked wrong option, its share, and a p-value against the guessing model. Curated cut from a July 27, 2026 export of 39,113 questions.
Cite as: "LearnClash Misconception Index, July 2026, Pluxia GmbH (learnclash.com)".
Use these files as they are. Do not recolor the icon, and keep the founder portrait uncropped beyond a square. Screenshots show the LearnClash 1.6.2 store set on the dark UI.
App Store ID 6756418938; Android package and iOS bundle ID com.learnclash.app.
For interviews, written quotes, or data requests about LearnClash or Pluxia GmbH, email admin@learnclash.com. David answers press mail himself, usually within 48 hours. Product and account questions go to support@learnclash.com.
Cite the product as "LearnClash (learnclash.com), a competitive learning app by Pluxia GmbH, Baar, Switzerland", with the date you accessed the page. Cite the datasets by name, month, and publisher as shown above. Attribution with a link is all we ask.
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