KAnki: Universal Flashcard App for Kindle

KAnki is a spaced repetition flashcard application designed specifically for jailbroken Kindle devices. It helps users learn vocabulary in any language through digital flashcards with a spaced repetition system.

Huge thanks to PolishPenguin for lending a hand — couldn't do it without them!

✨ New Update: Üben + KAnki Workflow

You can now use Uben as a companion tool to manage your decks more easily.
Since Kindle itself cannot process .apkg files directly, the workflow is:

1. Find a deck on Anki (e.g., shared decks online).
2. Import the .apkg into Uben.
3. Edit, add, or update cards using Uben’s modern UI.
4. Export from Uben → generates a kanki_config.js.
5. Transfer kanki_config.js to your Kindle (replace your existing file).
6. Launch KAnki on your Kindle with the new deck.

Advantage of this approach:
- You get a much better UI for editing and creating decks for KAnki on Uben.
- Once you’re done, you just export the ready-to-use configuration to your Kindle.
- No need to manually type out decks on Kindle anymore!

Community - For more information / doubts / suggestions join our discord - https://discord.gg/JtcrpG7ECA

Features

• Universal language support: Learn any language by simply changing the font and vocabulary
• Spaced repetition system to optimize learning
• Customizable vocabulary flashcards with any proficiency levels
• Filtering by level (JLPT, CEFR, HSK, or any custom system)
• Star/favorite system: Mark important cards and filter by starred items
• Reversible cards: Switch between target language → native and native → target language modes
• Per-card statistics: Track how many times each card has been viewed and review history
• Error review mode: Review cards you answered incorrectly right after completing a session
• Centralized configuration: Easy customization through a single configuration file
• E-ink optimized UI: Fixed element heights and visibility management to minimize screen refreshes
• Data persistence: All study progress and card statistics are automatically saved between sessions

Technical Limitations

• The app is designed for jailbroken Kindle devices with very limited browser capabilities
• Uses older ES5 JavaScript only (no modern JS features)
• Limited CSS support (no flexbox, grid, CSS variables, etc.)

Setup Instructions

Prerequisites

• A jailbroken Kindle device
• Access to the Kindle's filesystem
• Basic knowledge of file transfer to Kindle

How to Install KAnki ( New Users )

1. Clone this repository or download it as a ZIP file
2. Connect your Kindle to a computer via USB
3. Unzip the downloaded file (Make sure the name is KAnki)
4. Copy the KAnki folder and the kanki.sh script to the documents folder on your Kindle
5. Open the kanki/js/kanki_config.js file and edit the configuration to match your language.
6. Download or convert a TTF font file that supports your target language. Rename it to language.ttf and place it in: kanki/assets/fonts/language.ttf
7. Disconnect your Kindle from the computer
8. Open the Kindle's home screen and run the KAnki app

🔧 How to Update ( New Users ignore this )

1. Back up your current kanki/js/vocabulary.js or kanki/js/kanki_config.js file if you have been using KAnki, ignore if you are a new user
2. Download the new KAnki release
3. Replace your old KAnki folder with the new one
4. Copy your vocabulary data to the new kanki/js/kanki_config.js file
5. Optional: Customize language settings in kanki_config.js
6. Copy your language.ttf font file to the new kanki/assets/fonts/language.ttf location
7. Disconnect your Kindle from the computer
8. Open the Kindle's home screen and run the KAnki app
9. Hit the Reload button after clicking the 3 dots in the top chromebar in the app to apply changes.
10. Done! Your KAnki app is now updated with the latest features including the new star/favorite functionality

Note for users updating to the starred cards version: When updating from a previous version without the star functionality, all your existing cards will initially be unstarred. You'll need to manually star your important cards after updating.

Customizing for Your Language

KAnki makes it easy to study any language by changing just a few files:

1. Prepare the font for your target language

Download or convert a TTF font file that supports your target language. Rename it to language.ttf and place it in:

kanki/assets/fonts/language.ttf

2. Update the configuration file

Edit kanki/js/kanki_config.js to include your language configuration and vocabulary:

/**
 * KAnki Configuration
 * Edit these settings to customize the app for your language
 */
var KANKI_CONFIG = {
  language: "Spanish",  // Change this to your language name
  levels: ["A1", "A2", "B1"]   // These should match the keys in your VOCABULARY object
};

/**
 * Vocabulary Data
 * Organized by proficiency level
 */
var VOCABULARY = {
  "A1": [
    {"front": "hello", "back": "hola", "notes": "Greeting"},
    // Add more words...
  ],
  "A2": [
    {"front": "tomorrow", "back": "mañana", "notes": "Time"},
    // Add more words...
  ],
  // Add more levels...
};

For languages with different writing systems, use the reading property:

{"front": "こんにちは", "reading": "konnichiwa", "back": "Hello", "notes": "Greeting"}

Web Editor for Flashcards by Kindlemodshelfguy

For an easy way to manage your flashcards visually, you can use the KAnki Web Editor:

• Web Editor: https://kindlemodshelf.me/editor.html

This online editor allows you to: - Upload your existing flashcard configuration files - Add, edit, and delete cards and decks through a user-friendly interface - Preview how your flashcards will look on different Kindle generations - Export your modified configuration back to your Kindle

Converting to Anki Format

If you want to convert your KAnki configuration to Anki's .apkg format for the desktop/mobile Anki application, you can use the KankiToAnki converter:

• GitHub Repository: https://github.com/crizmo/KankiToAnki
• Web App: https://kankitoanki.vercel.app/

Data Storage

KAnki saves your progress and card statistics using the Kindle's localStorage feature. All your data is stored locally on your device at:

/Kindle/.active_content_sandbox/kanki/resource/LocalStorage/file__0.localstorage

If you ever want to reset all progress or encounter issues with saved data, you can:

1. Delete this file to completely reset the application data
2. Use the "Reset Progress" button within the app to only reset card progress while keeping your deck intact
3. Use the "Reset All" button to return to the default deck and clear all progress

Development

Project Structure

kanki.sh             # Startup script
kanki/
  config.xml         # Application configuration
  index.html         # Main HTML file
  main.css           # Styles
  main.js            # Application logic
  assets/
    fonts/
      language.ttf     # Language font file
  js/
    kanki_config.js  # Language configuration and vocabulary
    polyfill.min.js  # ES5 polyfills
    sdk.js           # Kindle-specific functions

Technical Details

• The app uses ES5 JavaScript for compatibility with Kindle's older browser
• XMLHttpRequest is used instead of fetch for API calls
• Custom language fonts are supported for proper character rendering
• Local storage is used to save flashcard progress
• Card objects include a starred property that persists with the deck data

Known Issues

• UI rendering issues due to different Kindle screen sizes

Acknowledgements

• Inspired by the Anki spaced repetition software
• Special thanks to the Kindle jailbreak community
• For more information / doubts / suggestions join our discord - https://discord.gg/JtcrpG7ECA