cbooks FAQ
Basic questions about cbooks, a free EPUB reader that runs in your web browser.
Is there a browser-based e-reader with good note taking?
Yes, that is what cbooks is built for. It is a free EPUB reader that runs in your web browser. Select text, then add a note, or mark the passage with one tap as Got it, Unclear, Key or Question. Your notes are searchable across all your books, collected into Review, Questions and Key lists, and can be saved as one plain text file (Notes (.md)), grouped by chapter. You can also send chosen notes to other people reading the same book.
It is an early test version, so expect rough edges. See the limits below.
What is cbooks?
cbooks (also called the cbook reader) is a free web page for reading EPUB books on a phone, tablet or computer. You open it in a browser, add EPUB files from your own device, and read them with clean pages laid out for your screen. It remembers where you read, lets you take notes and marks, and works offline after the first visit. There is nothing to install. Open the reader or read the About page.
Is cbooks an e-reader device or an app I install?
Neither. It is a web page. It runs on the screen you already have, such as a phone, tablet or computer, and it is not made for e-ink screens in particular. On a phone you can add it to your home screen from the browser menu. It is not yet an installable app.
Is it free? Do I need an account?
It is free, and there is no sign-in and no account.
Where are my books and notes kept? Are they uploaded?
On your own device, in your browser's storage for this site. The books you add are never uploaded, and the reader never receives your notes. Your place, bookmarks, notes and settings are saved in your browser too. Like any web site, the server keeps ordinary access logs of requests for its files. Browsers can clear a site's storage, so use Back up everything now and then.
Does it work offline?
Yes. The first time you open the reader with a connection, it saves its own files in your browser. After that it opens with no signal, and the books, notes and place on your device work offline too. Adding a book from a link and checking for a newer edition of a linked book need a connection.
Which book files does it open?
EPUB. Other formats may open, but only EPUB is tested. It does not turn Kindle files into books. If you have a PDF, you can ask an AI assistant to turn it into an EPUB using the PDF guide on the Make Book page.
How do I add a book?
Open the reader to see your Library, tap Add books, and choose one or more EPUB files from your device. Tap a book to open it. Next time, tap Continue reading to land on the same passage. You can also open a link to a book that someone sent you.
Can I move my notes to another device?
There is no automatic sync yet. Back up everything saves every note, mark and place for all your books as one text file. Restore loads it on this device or another one (add your books to the shelf again and they pick up where you left off). Notes (.md) saves one book's notes, and Download trail saves one book's trail.
What is a Trail?
The Trail is the reader's memory of how you read a book. It records where you settled, the jumps you made on purpose (Contents, links, the slider, bookmarks and notes), bookmarks and your notes. It finds your place again even after you change the font size.
Which browsers and devices does it work on?
It has been tested on an Android phone in the Brave browser and in desktop Chrome. It should work in other modern browsers, but iPhone and iPad have not been tested yet, and full screen in particular may work differently there.
Can I make my own books?
Yes. The Make Book page explains how to have an AI assistant research and write a book for you in about fifteen minutes. You download a guide, attach it to a chat with an assistant, paste a prompt, answer its questions, and add the EPUB file it gives you. The steps were tested with the free version of Gemini and with Claude Pro. The plain text guides are the authoring guide and the PDF guide. As with any book an AI writes, check the facts that matter to you.
Is cbooks the same as csBooks, Calibre-Web or Kavita?
No. cbooks is not related to csBooks, which is a separate e-book reader app, or to other products with similar names. It is also not a copy of a self-hosted library server such as Calibre-Web or Kavita. cbooks is one web page, made by Bill Mandel, that you open in your browser at friendsservermb.mine.nu/cbooks/.
What are the limits?
It is an early test version. There is no sync between devices (only backup and restore), no text-to-speech, and only EPUB is tested. EPUBs that contain scripts will not behave as their authors intended, because the reader blocks scripts other than its own. iPhone and iPad are untested. The Getting started guide inside the reader lists these and what may come next.
Who made it?
Bill Mandel built it with Claude Code, Anthropic's AI coding assistant. See how it was built. The reader uses the open-source foliate-js engine to display books. See the third-party notices.