Send2Kobo

Transfer files to your Kobo e-reader wirelessly using a simple pairing code.

Features

• Upload files from your computer or phone
• Download on your Kobo e-reader using a 6-character pairing code
• Server-rendered Kobo page (works on Kobo's limited browser)
• Supports all Kobo-compatible formats: EPUB, PDF, MOBI, TXT, CBZ, CBR, and more
• Sessions expire after 3 months (auto-extended on access)
• 5GB max file size

How It Works

1. On your computer: Visit https://your-site.web.app/upload, get a 6-character pairing code, and upload files
2. On your Kobo: Open the browser, go to https://your-site.web.app/kobo, enter the code, and download your files

The Kobo page (/kobo) is server-rendered via Cloud Functions, so it works on the Kobo's old WebKit browser which can't run modern JavaScript.

Supported File Formats

• Books: EPUB, PDF, MOBI, KEPUB
• Text: TXT, HTML, RTF
• Comics: CBZ, CBR
• Images: JPEG, PNG, BMP, TIFF, GIF

Tech Stack

• Frontend: SvelteKit + TypeScript + Vanilla CSS (no Tailwind - for e-ink compatibility)
• Backend: Firebase (Firestore + Storage + Cloud Functions)
• Hosting: Firebase Hosting

Setup

1. Create a Firebase Project

1. Go to Firebase Console
2. Create a new project
3. Upgrade to Blaze plan (required for Cloud Functions)
4. Enable Firestore Database (start in test mode)
5. Enable Storage (start in test mode)
6. Register a web app and copy the config

2. Configure Environment

Create a .env file with your Firebase config:

PUBLIC_FIREBASE_API_KEY=your-api-key
PUBLIC_FIREBASE_AUTH_DOMAIN=your-project.firebaseapp.com
PUBLIC_FIREBASE_PROJECT_ID=your-project-id
PUBLIC_FIREBASE_STORAGE_BUCKET=your-project.appspot.com
PUBLIC_FIREBASE_MESSAGING_SENDER_ID=your-sender-id
PUBLIC_FIREBASE_APP_ID=your-app-id

3. Install Dependencies

# Install frontend dependencies
npm install

# Install Cloud Functions dependencies
cd functions && npm install && cd ..

4. Run Development Server

npm run dev

Note: The /kobo endpoint requires Cloud Functions, so it won't work locally without the Firebase emulator.

Deployment

1. Install Firebase CLI

npm install -g firebase-tools
firebase login

2. Build the Frontend

npm run build

3. Build Cloud Functions

cd functions && npm run build && cd ..

4. Deploy Everything

firebase deploy --project your-project-id

Or deploy individually:

# Deploy hosting only
firebase deploy --only hosting

# Deploy functions only
firebase deploy --only functions

# Deploy Firestore rules
firebase deploy --only firestore:rules

# Deploy Storage rules
firebase deploy --only storage:rules

Project Structure

send2kobo/
├── src/
│   ├── routes/           # SvelteKit pages
│   │   ├── +page.svelte  # Home page
│   │   ├── upload/       # Upload page (for computers/phones)
│   │   └── download/     # Download page (modern browsers)
│   ├── components/       # Svelte components
│   └── lib/              # Utilities, Firebase config
├── functions/
│   └── src/
│       └── index.ts      # Cloud Functions (kobo page, download proxy)
├── static/               # Static assets
└── build/                # Production build output

Cloud Functions

• /kobo - Server-rendered download page for Kobo e-readers
• /download - Download proxy that sets correct filename headers
• cleanupExpiredSessions - Scheduled weekly (Sundays 3am UTC) to delete sessions expired 7+ days ago and their files

Development

# Start dev server
npm run dev

# Build for production
npm run build

# Preview production build
npm run preview

# Type check
npm run check

# Build functions
cd functions && npm run build

URL Parameters

• Upload page: https://your-site.web.app/upload?code=ABC123 - Reconnect to an existing session
• Download page: https://your-site.web.app/download?code=ABC123 - Auto-connect with code
• Kobo page: https://your-site.web.app/kobo?code=ABC123 - Auto-connect with code

CI/CD

The project uses GitHub Actions to automatically deploy on push to main. See .github/workflows/deploy.yml.

Set up the GitHub secret:

1. Go to Firebase Console → Project Settings → Service Accounts
2. Click "Generate new private key" → Download the JSON file
3. Go to your GitHub repo → Settings → Secrets and variables → Actions
4. Click "New repository secret"
5. Name: FIREBASE_SERVICE_ACCOUNT
6. Value: Paste the entire JSON content from the downloaded file

TODO

• Upgrade firebase-functions to latest version (cd functions && npm install --save firebase-functions@latest)