iOS and Android readers that can synchronize page tracking data

[stormerider]

Question for my fellow readers of the technical variety. I primarily read books via the Kindle app on both my iPhone and Android tablet. It’s a bit kludgy trying to read books acquired from other vendors than Amazon, and I would like to diversify a bit. I do have Calibre set up on my desktop, so converting between book formats such as EPUB vs MOBI is already solved for me... I regularly import all my purchases and convert them to the opposite format as a regular backup policy in the event of a sudden vendor closure (B&N Nook, looking at you, as they seem to have been in a corporate death spiral for several years at this point).

However, one of the biggest reasons that I currently use the Kindle app is their Whispersync feature. I primarily read on my tablet, but frequently switch to my iPhone when I’m outside having a smoke. Whispersync helps me easily flip between devices without having to manually move to the location I left off at on the other device.

I know that some of the available ebook reading apps support this kind of feature (I remember seeing that one [can’t remember which at the moment] stored the tracking information in Dropbox, which makes perfect sense to me as a mechanism to synchronize information between devices). However, I’m not aware of an app that has support for this feature that is also available for both Android and iOS. Nor am I aware of two apps that can interoperate on this kind of cross-platform synchronization. Is anyone aware of an app (or two apps) that will bridge this kind of gap that also supports directly synchronizing with my Calibre server, via ODPS or the like?