EZFurigana helps Japanese learners and teachers add accurate furigana to PDFs, EPUB ebooks, Word documents, SRT subtitles, images, and text while preserving original formatting. It achieved 98.8% token-based reading accuracy in an internal 7,500-line benchmark. Users can edit readings, ruby annotations, and styling. The service is free with account-based features and a freemium tier for higher usage limits.