Supported books & documents

Supported formats

.epub

Standard and most commonly used format to read book on digital platform. There are still a lot of work to be done but ultimately you should be able to have all the expected features from oboku (highlights, bookmark, reflow, reading direction and language support, ...). Whenever possible, please try to convert your document into epub format. You can use many tools for it (eg: calibre)

.cbz, .cbr

Theses are common format used for comic/manga archive. This is basically a zip or a rar file that contains a list of image files in it (.png, .jpg, ...). If you have a list of images and would like to be able to read as a book you can quickly create an archive and use it as it is.

.txt

Text documents format, oboku will let you open it and scroll through the content. The support is limited and you will not have most of the features than epub. It is recommended to convert it into an epub book.

Unsupported formats

.mobi

mobi is an old and closed format from amazon and we will not provide support for it. It requires a lot of effort and is very limited compared to epub. When possible convert your mobi files to epub. See more

Need a format not listed here ?

We try to support as many open standard as possible but if your format is not available yet please contact us and we will work on it if possible

General limitation per document

Due to server cost (it's free for you but not for us unfortunately) it is currently recommended that the document size must stay under 500mb. In addition to the size limitation and for oboku to be able to retrieve metadata of the said file, the server must be able to download and process it under 15mn maximum. That being said, epubs larger than 200-300mb are quite rares and if you have such books you can use tools like calibre to optimize the images inside in order to reduce the size. The time to process a book varies based on the size of the book and the latency of the data source. Most of the time data source like google, dropbox, etc should be fast enough but it is possible to experience slowdown from time to time and therefore even a small book could end up in timeout. You can try to manually refresh the books that appears to have failed to retrieve metadata.

Note that nothing blocks you from adding a book that is larger in size. Some of the features will not work properly such as retrieving metadata from your epub or displaying the cover (they require to download and access the file) but you will still be able to see it in your library, download it and potentially read it.