Useful ebook sync must identify the same book, save your reading state, and reconcile changes between devices. A matching filename alone does not prove that two readers share any of those things.
Test the four layers
Check the file, reading position, bookmarks, and annotations independently. A service might deliver the book correctly but leave the highlights in another app. Write down which layer matters most to your routine.
Use the same edition
A re-converted or updated EPUB can have a different internal structure. Percentages and location identifiers may no longer point to the same passage. Test the exact file you plan to keep reading.
Make a deliberate handoff
Read a chapter on device A, return to its library, and allow sync to finish. Open device B and check the position and a test note. Then repeat in the opposite direction, including one offline session.
The details, at a glance.
| Consider | What to look for |
|---|---|
| Book delivery | The same title arrives |
| Position sync | The next device opens at the right passage |
| Annotation sync | Notes and highlights appear with context |
| Conflict handling | Offline changes do not silently overwrite each other |
A few things worth asking.
Does an OPDS feed synchronize progress?
Catalog access and downloads do not, by themselves, provide a shared reading-position service.
Why do page numbers differ?
Reflowable books change pagination with screen size and type settings. Compare passages or chapter locations instead.
Go to the source
Documentation consulted for the routes and terminology on this page. Product behavior can change; verify your exact setup.
OPDS specifications W3C EPUB 3.3 specificationWritten by Binge Reader. Our comparisons explain documented workflows and practical tradeoffs; they are not independent product benchmarks.