Doiti - German Grammar Practice

A free, offline app to practice German grammar. Works on Android and the web.

Try it in your browser

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Practice Modes

The compact Pocket Decks menu opens Overall A1, Overall A2, Conversation, and a filterable library of all 19 grammar modes. Quick focus shortcuts jump straight to common topics. Warm paper cards and raised answer buttons carry through every activity, Settings, and session summary. Multi-gap cards show four choices for the active gap, advance to the next empty gap, and let you revisit any gap before checking. Conversation separates blue dialogue from amber objectives and keeps answer-revealing explanations behind a solved reply or an explicit reveal.

Correct answers get a small checkmark stamp and paper burst. Session combos earn brief sticker rewards at 3, 5, and every further 5 correct answers in a row. Completed decks reveal a fanned-card reward with accuracy and best combo; perfect runs get a special badge. Early exits show saved progress instead. Conversation combos count first tries only. Effects never block the next card and respect the device's reduced-motion preference.

Der/Die/Das Learn noun genders

Adjective Endings Master adjective declension

Case Identification Identify grammatical cases

• 303 curated German nouns (101 masculine, 102 feminine, 100 neuter)
• 30 adjective-noun pairs with 20 sentence templates
• 25 annotated case sentences for case identification
• Immediate feedback on answers
• Progress tracking (stored locally)
• No account required, no internet needed

Overall A1 and Overall A2

Two mixed grammar categories offer 3,037 exercises: 1,644 A1 and 1,393 A2, adapted from throughout the supplied A-Grammatik workbook:

• Fill one or several gaps by choosing from four options per gap.
• Choose conjugated verbs, including separable verbs and both parts of the Perfekt.
• Choose an answer and get an explanation after checking.
• Drag sentence pieces into numbered slots, swap placed pieces, or return them to the bank. Tapping and keyboard activation provide an alternative to dragging.

Opening a grammar or Overall deck immediately starts 20 mixed cards. The Settings tab saves a length of 5, 10, 15, 20, 30, or 50 cards and lets you include any combination of answer choices, gaps, conjugations, sentence puzzles, and matching. Preferences apply to the next session and persist on this device. Only relevant, selected types are mixed; small decks use fewer cards without repeats. If a deck has no matching types, it links to Settings. Conversation keeps its scenario menu and five objectives per scenario. Sessions prioritize unseen and weaker exercises. English translations are offered where available, mistakes can be reviewed at the end, and each level has its own progress and History entries. Existing saved progress is preserved.

The bank includes 2,917 distinct workbook adaptations plus the original 120 questions. Duplicate workbook questions retain all page references. Open-ended group discussions are not automatically graded. The PDF, artwork and audio are not bundled into the app. See the content notes and page-by-page coverage.

Progress

The Progress tab (formerly History, still reachable at /history) includes a local Monday–Sunday activity trail, a suggested next grammar deck, three small milestones, and a collection of 20 skills. Review recommendations put specific missed cards first and respect the exercise types and length saved in Settings. Recent sessions remain available in a collapsible log.

Explored counts unique answered cards. Familiar requires three recent correct attempts; older records use at least three attempts and 80% accuracy until enough new outcomes exist. Skill labels are practice signals, not proficiency grades. Shared workbook cards contribute to each relevant skill and count once in the collection totals. Daily activity is saved independently of the 20-session log; older activity is recovered only from dates present in that log.

Getting Started

Prerequisites

• Node.js 20+
• npm (comes with Node.js)

Install dependencies

npm install

Run on the web (development)

npm run web

Opens a local dev server. Works in any modern browser.

Run on Android (development)

npx expo start

Then press a to open in an Android emulator, or scan the QR code with Expo Go on your phone.

Build Android APK (cloud)

Requires EAS CLI and an Expo account:

npm install -g eas-cli
eas build -p android --profile preview

This builds an installable .apk file in the cloud.

Build Android APK (local)

No cloud service needed. Requires JDK 17 and the Android SDK (or Android Studio).

# 1. Set environment variables (adjust paths to your setup)
export JAVA_HOME=/path/to/jdk-17
export ANDROID_HOME=/path/to/android-sdk

# 2. Generate the native android project
npx expo prebuild --platform android --clean

# 3. Build the APK
cd android
./gradlew assembleRelease

The output APK will be at android/app/build/outputs/apk/release/app-release.apk. Transfer it to your phone and install.

Note: The android/ directory is generated by prebuild and is in .gitignore. You can use assembleDebug instead for a debug build that's auto-signed and easier to install.

Build for web (production)

npx expo export --platform web

Produces a static site in the dist/ folder, ready to deploy anywhere.

Deployment

The web app auto-deploys to GitHub Pages on every push to main via GitHub Actions.

Install on your phone

Visit the live website in Chrome on Android. When Chrome makes installation available, the Home screen shows Install Doiti. You can also use Chrome's menu and choose Install app or Add to Home screen. Chrome controls the timing of its installation offer; it may require a tap and a short visit first. On iPhone, use Safari's Share menu and Add to Home Screen.

The installed website uses the owl icon and opens in its own window. It uses the existing website and local progress storage; no account or app-store download is needed. Installation does not add offline caching: loading the website still needs an internet connection.

The manifest and icons are in public/, and app/+html.tsx links them on every page using the configured GitHub Pages base path. The installation banner is web-only, hides in standalone mode, and appears only on Home when the browser provides a real install prompt. It never interrupts an exercise.

Tech Stack

• React Native + Expo (managed workflow)
• TypeScript
• Expo Router for navigation
• react-native-web for browser support
• AsyncStorage for local progress tracking
• GitHub Actions for CI/CD

Project Structure

doiti/
  app/                    # Expo Router screens
    (tabs)/
      index.tsx           # Home dashboard
      gender.tsx          # Der/Die/Das quiz
      adjectives.tsx      # Adjective endings exercise
      cases.tsx           # Case identification exercise
    _layout.tsx           # Root layout (responsive web wrapper)
  components/             # Shared UI components
  data/                   # Bundled data files (nouns, adjectives, cases)
  lib/                    # Utilities (types, declension, stats, quiz logic)
  constants/              # Theme colors and spacing
  assets/images/          # App images and icons

Contributing

Contributions are welcome! Some ideas:

• Add more nouns, adjective pairs, or case sentences to data/
• Add new exercise types (e.g., verb conjugation, preposition practice)
• Improve the UI/UX
• Add accessibility features
• Add more languages

How to contribute

1. Fork the repository
2. Create a feature branch (git checkout -b feature/my-feature)
3. Make your changes
4. Test on both web (npm run web) and mobile (npx expo start)
5. Commit and push
6. Open a pull request

Data Sources

• German nouns: curated from gambolputty/german-nouns (CC-BY-SA-4.0)
• Adjective templates and case sentences: hand-crafted
• Overall A1/A2: newly authored exercises following the grammar topics and task formats in A-Grammatik: Übungsgrammatik Deutsch als Fremdsprache, Anne Buscha and Szilvia Szita, SCHUBERT-Verlag (2010); local reference: book.pdf.

License

This project is open source. Data files are licensed under CC-BY-SA-4.0.

Focused practice

All 19 focused modes now use the same no-typing experience as Overall practice. They include sentence dragging, clickable answers, and matching boards for comparisons, opposites, and similar meanings. Existing exercises and progress are preserved, and book-question progress is shared across modes. See the focused practice rollout for coverage and controls.

Workbook cards use an explicit task-level classification rather than their chapter headings. See the book content audit for the findings, per-deck counts, and rules for reviewing new imports.

Conversation adds ten everyday scenarios with five objectives each. Build replies word by word using four choices per slot, correct mistakes, and follow the dialogue. See Conversation practice.