EPUB Translator

[Haagendazs]

I've been working on a Windows tool for translating EPUB e-books using the OpenAI API and wanted to share it here since this community knows EPUBs better than anyone.

What it does: Reads an EPUB, translates the text chapter by chapter using GPT-4.1 or similar models, preserves HTML structure, rebuilds NCX/NAV table of contents, and outputs a valid EPUB that opens correctly in Calibre.
Technical details for those who care: It parses each XHTML file with BeautifulSoup, walks the DOM to find translatable text nodes, masks URLs/acronyms/Roman numerals before sending to the API, restores them after, promotes class-hinted headings to h1 where needed, and injects Kindle-compatible CSS. Drop-cap spans are merged with their following text before translation to preserve word context.
Cost: ~$4–6 per novel via your own OpenAI API key. One-time app purchase.

https://hauzirek.gumroad.com/l/epub-translator