The documentation says JabRef integrates with Latex. Does it work with Overleaf?
Yes, LaTeX works. Since JabRef uses .bib as their database format, you will very likely be able to manually import your .bib library into Overleaf. I personally have not tried to do so, so I can only speculate.
There are attempts to integrate Overleaf more tightly with JabRef, but they are a little bit stuck at the moment. Any help is welcome. Here is the corresponding issue at GitHub: Synchronization with Overleaf #156