Tools

Open-source e-book manager whose command-line tools (ebook-convert, ebook-meta, calibredb) batch-convert between EPUB, MOBI, AZW3, PDF, DOCX and more and manage library metadata. The install command is Linux-only; on macOS and Windows use the installer.

Uses LLMs to translate EPUB, TXT, Markdown, SRT, PDF and other files into side-by-side bilingual editions, via OpenAI, Anthropic, Gemini and other APIs or DeepL and Google Translate. LLM APIs need your own key or a Codex subscription. Only translate content you have rights to.

LLM translator for novels, subtitles, ebooks and game text: one-click glossaries keep names consistent and translations get auto-reviewed. Besides the desktop app it has a CLI (translate/analyze, JSONL status). Download from Releases and bring an LLM API; commercial use needs the author's OK.

Translates whole EPUB books, Word files, SRT subtitles and TXT with local Ollama or cloud LLMs (OpenAI, Gemini, DeepSeek), keeping layout and timings. Builds a glossary for consistent terms and can resume jobs. Mainly a desktop app; the CLI runs from source; cloud models need an API key.

The official W3C conformance checker for EPUB, maintained by the DAISY Consortium: finds issues that break the EPUB 2/3 specs and outputs a report, so self-publishing authors and editors can check books before release. Needs Java; download a release and run it with java -jar.