You have an eBook and nothing on your computer will open it. If it is an EPUB, upload it to Doconut.app and it opens in the browser, free, with no reading app and no account.
If it is a MOBI, this is the wrong page, and it is better to say so in the first paragraph than three screens down. The eBook viewer here accepts EPUB only. MOBI is Amazon's older Kindle format, it is not in our catalogue, and uploading one will simply be refused. Most sources that hand you a MOBI will also offer an EPUB — ask for that instead, since Amazon itself retired MOBI in favour of newer formats.
The rest of this article is about EPUB, which is what schools and libraries actually distribute.
Why an EPUB Will Not Open on Its Own
An EPUB is not really one file. It is a zip archive holding the chapters as HTML, plus the cover, the fonts and a table of contents. That is why double-clicking one does nothing on a computer with no reading app: the system sees an extension it was never taught, and stops.
It is also why the format is worth having in education:
- It reflows. The same file reads correctly on a phone and on a lecture-hall projector, because the text rewraps instead of scaling.
- It is portable. A whole reading list travels as files rather than as a shelf.
- It is open. Almost every publisher and library exports to it, which is precisely why it is the format we support.
What the EPUB Reader Does
1. Renders the publisher's own layout
Chapters arrive with the publisher's fonts and images intact, and the table of contents becomes a menu you can jump around with.
2. Resizes the text properly
Make the type bigger and the paragraph rewraps to fit. Lines never run off the edge of the screen — which is the point of EPUB and the thing a PDF of the same book cannot do.
3. Searches the whole book
Look for a phrase and it is found across every chapter, not only the page you are on.
4. Prints what you need
Send one chapter, or the whole book, to a printer with the layout intact.
5. Works on a phone
The reader is a web page, not an app, so it behaves the same in Chrome, Safari, Firefox and Edge, on a laptop or a handset.
6. Deletes your file afterwards
The upload is removed once you close the book. That matters when the manuscript is not published yet.
Books up to 25 MB. Over that, the upload is refused rather than left to fail slowly.
Who Can Benefit from Opening an EPUB on Doconut.app?
Professors
- Check that an EPUB you are about to set as reading actually renders before thirty students discover it does not.
- Read a book on a classroom machine where you cannot install software.
Students
- Open a set text on a library computer, without an account and without installing anything.
- Search the whole book for the passage you need to cite.
Educational Institutions
- Check how an EPUB renders before it goes into an LMS or an intranet.
- Give staff a way to read a book on a locked-down laptop.
How to Get Started
- Upload the EPUB. Drag it onto the page, up to 25 MB.
- Read it. Chapters, search and printing all work from the same screen.
- Close the tab. Your file is deleted.
If what you have is a MOBI, none of the above applies. Convert it with a desktop tool such as Calibre, or ask whoever sent it for the EPUB, which they almost certainly have.
One More Thing, for the Developers Reading
If you are building the LMS rather than using it, the engine behind this page is licensed as the Doconut .NET SDK: 75 file extensions across 18 families, rendered on your own servers, with nothing leaving your network. The free viewers here cover 73 of those.
Everyone else: visit Doconut.app, upload the EPUB, and read it.