As of June 28, 2021, Amazon will no longer accept the MOBI file format for publications with reflowable layouts. This decision applies to both new releases and file replacements. 


  • For new releases with reflowable layouts, we will only send EPUB files to Amazon moving forward.

    • Publications with MOBI files can still be sold through Cantook Boutique or any other bookseller that supports this file format.

  • Updating reflowable ebooks:

    • If a publication's update is solely a metadata change and the MOBI file was previously uploaded, there is no need to submit an EPUB file. The previously submitted MOBI file will remain available for sale and its metadata will be updated as normal.

    • If a publication's update involves changes to the ebook's file contents, only EPUB files will be accepted.

  • In regards to fixed-layout formats, Amazon will continue to support MOBI files. Remember that Amazon still does not support fixed-layout EPUB files.

Cantook Hub will now auto-detect the layout of MOBI files. We will change our configuration for Amazon to send MOBI files first if the ebook is fixed-layout and reflowable EPUB files in all other cases. It will also be possible to upload an EPUB file in the MOBI format tab to keep the same product ID when updating the file.

Use cases

  • If a publication that has a reflowable MOBI format in its MOBI or EPUB tab that has been previously successfully submitted:

    • The metadata update will be submitted even if there is no longer a suitable file for Amazon in the format tab. 

    • The metadata and file updates will be submitted once a reflowable EPUB file is added in the format tab.

  • Adding a new publication with a fixed-layout MOBI will be submitted to Amazon.

  • Adding a new publication with a reflowable MOBI file and no other file will not be submitted to Amazon. However, it will be possible to still sell it through Cantook Boutique or any other bookseller that supports this format.

  • Should a new publication be added with both reflowable MOBI and reflowable EPUB files, it is the reflowable EPUB file that will be submitted to Amazon.

These changes will be rolled out in the week leading up to June 28.