calibre

About

Calibre is a free and open-source e-book manager, originating from Canada, that provides a comprehensive solution for digital book enthusiasts. As a FOSS project, it operates without a traditional revenue model, formal leadership, or employee count, relying on its developer Kovid Goyal and community contributions. Its extensive product portfolio includes robust library management, versatile format conversion (supporting all e-book formats, including EPUB to PDF), syncing to devices, an integrated e-book viewer, and an editor, alongside metadata management and custom cover image support. Key features emphasize privacy, offering internet-independent operation, no registration, and no tracking, coupled with text-to-speech, news downloads as e-books, and extensibility via plugins. Available across Mac, Windows, Linux, BSD, and various self-hosted and package manager options, Calibre has historically held a strong market position, once considered a pioneering and unrivaled tool in e-book management. While lauded for its powerful functionality and being 'one of the most helpful apps ever,' it also faces criticism for its user experience (UX/UI), perceived clutter, slow rendering, and developer's handling of bug reports, with some users noting issues with core features and file duplication. Despite these challenges, it remains a highly multifunctional and essential tool for many.