Is it legal to build/sell an engine on top of UE4?

If I want to build a specialized engine and power it with UE4, then license access to that engine and allow users to sell their content via a private marketplace, is that fair game?

My understanding from the EULA is that it is fair game and Epic would simply take a 5% cut out of the private marketplace content that was sold. Is that correct?

Thanks in advance!

You need to make a contact to the Epics,cause if you will use any libs inside of UE4,and distrubute them as your own solution,you need to have the licences to this libs.Hope it helps.You are going to use it in B2B.

No it is not legal. Epic will not permit it as you are forbidden to sell editor tools that link directly against editor parts of engine. What you can do is make your product and then make specialized build of editor specific to your product to create mods for example (you must distribute the engine build for free think). That was done numerous times. ArkKit, RoboRecall, some bus simulator…

Hi, I think you’re confused, I’m not talking about using the editor tools themselves in any way.

that is still not fair play u cant just make ur engine which is powered with ue4 and sell/put it for download.

like if you’re making one of those rpg makers?
I suppose if your customers are fine paying both you and epic it might be alright. though inconvenient.
definitely a grey area though. probably should use something else if you can’t get a clear answer. maybe godot?

Can you clarify what you mean by “specialized engine”?

I haven’t seen any place in the EULA where it says that you cannot create a custom game creation tool. By custom I mean that isn’t simply a modified UE4 editor, but instead was created from scratch, just linking the UE4 rendering and UI libraries. I’d like an official answer on this, please.
Of course, it’s common sense that they wouldn’t like someone to create a tool that’s almost the same as their editor, but how about something that’s simplified/specialized? Like if I wanted to create the “RPG in a box”(rpginabox dot com) engine, would it be OK? Would it be OK if there was a private marketplace for my editor? Of course, royalties would be due for any revenue coming from the marketplace or editor.