Making Project Opensource

Hi,
we are working on a project of which the backend (none Unreal code) is opensource.

If we want to make all the “unreal” front end opensource can we do that?

what about if we have purchased assets from the asset store, can our project be opensource and as long as those assets are used with this game only (written in some licence/readme file), would that be ok?

anyone able to help?

Unfortunately, this is not permitted.

thanks.
is that just because of the assets? so we could release all the code except for any assets used?

No, under the EULA you are not permitted to distribute source. There are a few exceptions, like to other UE4 licensees, but general public distribution is prohibited.