Features

Everything below works during the 14-day trial and, after it, with Ko Books or Plus. What Plus adds is at the end.

The library

Add files or whole folders, or drop them on the window: EPUB, KEPUB, FB2, FB2.ZIP, PDF, MOBI, AZW3 and TXT, up to 4 GB each.
Each book is copied into the library folder you choose, sorted by author and title. The files you added are never changed.
Title, author, series, language, tags and covers are read from the book; fix any of them by hand.
Authors, series, tags, favourites and your own collections in the sidebar; probable duplicates found as books are added.
Search across titles, authors and series as you type, in a library of tens of thousands of books.
A cover grid with an A–Z rail, or a list with columns; Continue reading at the top.
A backup of the catalogue every day, a trash you can undo, and a check for files that went missing.

Its own reader for EPUB, FB2 and PDF, with contents, search in the book, bookmarks, and your place kept.
Text size, font, line spacing and margins; pages or scroll; light, paper, dusk and dark themes.

Kobo, Kindle, PocketBook and tolino over USB, Android readers over USB (MTP), or any memory card or USB drive.
Choose books and Send: each copy is written, then checked. Nothing already on the device is changed or removed.
A book in a format the device can't read is converted on the way, where Ko Books can.
Send to Kindle by email, from your own email account. Its password stays in your system's credential store.

FB2 to EPUB, and EPUB or FB2 to KEPUB, which adds page numbers and footnotes on a Kobo.
A converted copy sits beside the original; the original is never replaced.
Protected (DRM) books are never converted or unlocked.

Import a Calibre library: books, authors, series, tags and covers.
Calibre's database is only read, from a copy. Running the import again adds only new books.

No account, no ads, no analytics, no crash reports.
Ko Books goes online only to activate or check its licence, when you buy, and when you send to Kindle. The privacy policy lists each request.

Plus includes everything in Ko Books and adds features as they arrive. None of them is out yet; we don't promise dates.