epub2mobi.py

epub2mobi.py is a zero-dependency Python tool that converts EPUB files to legacy MOBI6 for older Kindle devices.

It writes PalmDB/MOBI structures directly with the standard library and focuses on robust, text-first output.

Features

• Zero dependencies (python3 only).
• EPUB parsing via OPF manifest/spine with path normalization for ZIP internals.
• Table of Contents generation with fixed-width filepos links.
• TOC labels prioritized from NCX nav labels, then headings/titles, then body snippets/fallbacks.
• PalmDOC compression (type 2), applied per 4096-byte uncompressed text record.
• Legacy-compatible content sanitization (text/paragraphs/basic inline tags).
• Optional USB deploy to Kindle documents folder (--deploy).

Requirements

• Python 3.10+

CLI Usage

Convert:

python3 epub2mobi.py my_book.epub

Convert and deploy to a connected Kindle:

python3 epub2mobi.py my_book.epub --deploy

Module Usage

from epub2mobi import parse_epub, MobiWriter

epub_data = parse_epub("my_book.epub")
MobiWriter(epub_data).build("my_book.mobi")

Scope and Limitations

• Output target is MOBI6 (not AZW3/KF8).
• Text-first conversion: advanced CSS, JavaScript, embedded fonts, and rich modern layout are not preserved.
• Images are currently not emitted into MOBI records.
• XHTML decoding supports BOMs and declared encodings, with fallback behavior for unknown encodings.
• XML guardrails reject entity declarations and oversized XML payloads.

License

MIT License.