Rekapu

Learn while procrastinating

Transform your distractions into learning moments with scientifically-proven spaced repetition.

Features • Installation • Usage • Development • Contributing • Changelog

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What is Rekapu?

Rekapu is a browser extension that combines spaced repetition learning with website access control. Instead of blocking you with a wall, it shows you flashcards when you visit distracting websites. Your knowledge grows while your focus improves - no extra apps, no dedicated study time, just learning integrated into your day.

The key difference: Unlike traditional website blockers that redirect you to a new page (losing your scroll position and context), Rekapu uses an overlay approach. After answering a card, you continue exactly where you left off - no reload, no lost context.

Features

🧠 Spaced Repetition

Science-backed algorithm that shows cards at optimal intervals. Rate difficulty (Again, Hard, Good, Easy) and let the algorithm handle scheduling for maximum retention.

🔊 Text-to-Speech

Listen to your cards with natural voice synthesis powered by Google TTS. Perfect for audio learners and language practice. Requires your own API key.

📊 Daily Goals & Streaks

Activity calendar visualizes your consistency. Build learning streaks, hit daily goals, and watch your progress compound over time.

📦 Anki Import

Already have decks in Anki? Import plain text (.txt) or Anki package (.apkg) files instantly. No need to recreate your cards - bring your existing knowledge base.

✍️ Markdown Support

Format cards with markdown syntax. Add code blocks, lists, bold text, links, and embed images. Live preview while editing ensures cards look exactly as intended.

🎴 Multiple Card Types

• Basic (Show Answer): Traditional flashcard with front/back
• Cloze Deletion: Fill-in-the-blank with {{c1::text}} syntax, supporting multiple deletions per card

🔒 100% Private

All data stored locally in your browser using IndexedDB. No servers, no tracking, no accounts. Your cards and browsing habits stay completely private.

🌍 Multi-language Support

Currently available in English, Russian, and Ukrainian. More translations welcome!

Installation

From Chrome Web Store

Install Rekapu directly from the Chrome Web Store:

→ Add to Chrome

Supported Browsers

Any Chromium-based browser: Chrome, Brave, Edge, Opera, Vivaldi (version 88 or higher)

From Source (For Developers)

If you want to contribute or modify the extension:

1. Clone the repository:

   git clone https://github.com/k-tkachov/rekapu.git
   cd rekapu

2. Install dependencies:

   npm install

3. Build the extension:

   npm run build

4. Load in your browser:

   • Open Chrome/Brave/Edge and navigate to chrome://extensions/
   • Enable "Developer mode" in the top right
   • Click "Load unpacked" and select the dist folder
   • The Rekapu extension is now installed!

Usage

Quick Start

1. Add domains to block

   • Click the Rekapu extension icon
   • Go to "Domains" tab
   • Add sites you want to block (e.g., twitter.com, reddit.com)

2. Create your first cards

   • Go to "Cards" tab
   • Click "Add Card"
   • Write your question and answer
   • Use markdown for rich formatting

3. Configure settings (optional)

   • Adjust cooldown periods (global or per-domain)
   • Set daily study goals
   • Customize theme and display options

Creating Cards

Three ways to add cards:

1. Manual creation: Click "Add Card" in the extension popup
2. Quick capture: Select text on any page, right-click, and choose "Add selection as card"
3. Import from Anki: Import Anki decks in plain text format (.txt) or Anki package format (.apkg)

Card types:

# Basic Card
Front: What is the capital of France?
Back: Paris

# Cloze Deletion Card
The capital of {{c1::France}} is {{c2::Paris}}.

Studying Without Blocking

Open the extension popup and click "Study Due Cards" to review all cards in one focused session. When you're done, all blocked sites become accessible again.

Development

Project Structure

src/
├── background/         # Background service worker
├── content/           # Content scripts (overlay blocking)
├── popup/             # Extension popup UI (React + Chakra UI)
├── dashboard/         # Main dashboard UI (React)
├── storage/           # IndexedDB storage management
├── spaced-repetition/ # SR algorithm implementation
├── tts/               # Text-to-speech providers
├── utils/             # Shared utilities
└── _locales/          # Translation files (en, ru, uk)

Tech Stack

• Framework: React + TypeScript
• UI Library: Chakra UI (Material Design 3-inspired dark theme)
• Storage: IndexedDB (100MB+ capacity)
• Markdown: marked.js with live preview
• Build: Webpack
• Extension: Chrome Manifest V3

Development Commands

npm run build       # Production build
npm run build:dev   # Development build
npm run watch       # Development with file watching
npm test           # Run test suite
npm run lint       # Check code style
npm run type-check # TypeScript validation

Architecture Highlights

Overlay Blocking System

Rekapu uses an innovative iframe overlay approach that preserves page state, scroll position, and JavaScript context. This provides a seamless experience compared to traditional redirect-based blocking.

Benefits:

• ✅ Page state preserved
• ✅ Zero additional load time
• ✅ Seamless user experience

Universal Markdown Rendering

• Same renderer (marked.js) used in card editor and blocking interface
• Isolated CSS prevents theme conflicts
• Live preview with scroll synchronization
• Consistent rendering across all contexts

Efficient Storage

• IndexedDB for high-performance local storage
• Indexed queries for spaced repetition optimization
• Storage usage monitoring and intelligent cleanup
• Supports 100MB+ capacity

Contributing

We welcome contributions! However, at this time we are only accepting:

• 🌍 Translations - Help localize Rekapu for more languages
• 🐛 Bug Fixes - Fix existing issues and improve stability

We are NOT currently accepting:

• ❌ New features
• ❌ Major refactoring or architectural changes

Please read our Contributing Guidelines for detailed information on how to contribute translations or bug fixes.

License

Rekapu is licensed under GNU General Public License v3.0 (GPL-3.0).

This means:

• ✅ Free to use, modify, and distribute
• ✅ Derivatives must also be open source (GPL-3.0)
• ✅ Commercial use is allowed
• ✅ You must disclose source code of any modifications

See LICENSE file for full details.

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Made with ❤️ for learners everywhere

Licensed under GPL-3.0