Parsing and Rebuilding EPUB Files in Python: Lessons Learned from Building an AI Translation Service

How we extract, translate, and reconstruct entire ebooks with Python while preserving every detail At LectuLibre, we built a service that translates entire books using large language models. Our users upload EPUB files, and our backend pipeline parses them, extracts the text, sends it to an LLM for translation, and then rebuilds the EPUB with the translated content—all while preserving the original formatting, images, and metadata. This sounded straightforward until we looked inside a real EPUB...