Kobo Highlight Exfiltrator

A simple, statically-linked binary to extract highlights from your Kobo e-reader.

Features

• Zero dependencies: Fully statically linked with musl libc and SQLite
• Cross-platform: Builds for both x86_64 (development) and ARM (Kobo)
• Small binary: ~780KB for ARM release build
• Simple: Just point it at your KoboReader.sqlite database

Building

For local testing (x86_64)

zig build
./zig-out/bin/kb_exfiltrator local-dev.sqlite

For Kobo (ARM)

./build-kobo.sh
# or manually:
zig build -Dtarget=arm-linux-musleabihf -Doptimize=ReleaseSmall

Usage on Kobo

1. Copy zig-out/bin/kb_exfiltrator to your Kobo (via USB or SSH)

2. Run:

   ./kb_exfiltrator /mnt/onboard/.kobo/KoboReader.sqlite
   

3. Or save to a file:

   ./kb_exfiltrator /mnt/onboard/.kobo/KoboReader.sqlite > highlights.txt
   

How It Works

The program:

1. Opens the SQLite database at the path you provide
2. Queries the Bookmark table for all highlights (entries with non-NULL Text)
3. Displays each highlight with:
   • Date created
   • Book identifier (ContentID)
   • Highlight text
   • Any annotations/notes you added

Dependencies

All dependencies are bundled into the binary:

• SQLite 3.48.0 (amalgamation build)
• musl libc (for ARM target)

Requirements

• Zig 0.15.2 or later

Notes

• The binary is statically linked, so you can copy just the single file to your Kobo
• Uses musl libc for smaller binary size and better portability
• SQLite is compiled with:
  • SQLITE_THREADSAFE=0: No threading support (smaller, faster)
  • SQLITE_OMIT_LOAD_EXTENSION: No dynamic extensions (more secure)