Our apps currently do not support import, export or syncing with the bookmarks of the DuckDuckGo web browser because the DuckDuckGo web browser does not support browser extensions.  Our apps would require our BookMacster Sync extension to be installed into the DuckDuckGo web browser.

Of course, we could work around the problem by maintaining reverse-engineering for the DuckDuckGo web browser, as we do with Safari and iCloud.  (Safari only partially supports browser extensions, and the part that we need for bookmarks syncing is not supported by Safari.) 

But this reverse-engineering has been a massive effort, and is still fragile.  We did it for Safari because all Mac users use Safari, and we have supported Safari since 2005 when the reverse-engineering was very easy.

But we're not going to do that for DuckDuckGo.

This article seems to be a recent (June 2023) statement from DuckDuckGo regarding the situation.

(Scroll down in that article to Extensions and the Windows browser.  Apparently it's the same for the Mac browser which I believe was published earlier.)  Short version: Extension support is envisioned at some undetermined point in the future.

If any DuckDuckGo web browser user wants to monitor that situation, let us know when DuckDuckGo supports extensions and we shall have a look at it.