First of all i would like to give a huuuuuge thanks and a hug to the creator of this patch, without it nothing of it would be possible, if anyone knows his Steam please comment below so i can give him the credits but anyways, his github is xADDBx

First of all you guys need to download this thing here from his github:

https://github.com/xADDBx/Isaac-Online-Modded

After you have download it, you need to open it and patch your isaac-ng.exe file, the default folder should be (C:/Program Files (x86)/Steam/steamapps/common/The Binding of Isaac Rebirth\isaac-ng.exe)

With the game's .exe patched it will allow you to load mods normally in the menu and getting online without asking you to turn mods off and restarting the game to be able to acess the online option.

You need to reapply the patch everytime the games gets updated (currently the game is at 1.9.7.8)

Note: Your windows or antivirus will probably gives you a heads up for the file being "a trojan", don't worry about that is a false positive, i will post xADDBx it's own words about it below:

xADDBx commented 2 weeks ago •
The tool patches the game's binary to change how it behaves.
Some trojans/malware do bad stuff in a similar way, so AVs flag the file because it's suspicious.

You can look at the code; The release file is just the compiled project.
The Project does 3 things, GUI, finding the exe and patching. The patching can be seen here: https://github.com/xADDBx/Isaac-Online-Modded/blob/master/IsaacOnlineModded/GamePatcher.cs#L60

Example:
This is the release file on VirusTotal. Notably flagged from 25/72 Vendors.
This is the same compiled project, just with a black icon, on VirusTotal. I only added an icon to the file, and now only 13/72 Vendors flag the file. As this hopefully clarifies, AVs like to flag things based on being somewhat similar to other software, which, especially for small tools like this one, can often result in false positives. (

It's important to say that allowing some mods will cause desync, but the author on github said that if all players have the same mods installed and enabled that won't happen (meaning this is awesome to play along with friends)

But some mods don't cause desync at all, even if you are the only person with that mod installed (for example: EID External Item Descriptions) this one in fact is the one that made me search the entire internet to find a method of how to use mods in online, cause i can't really play without it.

Note: I didn't tested my other mods cause i still didn't catch up with the few friends i have to test a run with everyone with the same mods installed.

Note 2: I didn't tested and didn't heard a word about class mods to work, but i highly doubt this would work even if everyone has for example (Class mod Mei installed) but i could be wrong, if you guys have the time and the team to test it and works, let me know in the comments.

In order for EID works correctly you need to change two values from false to true in the main.lua of the mod by default it should be located at
(C:\Program Files (x86)\Steam\steamapps\common\The Binding of Isaac Rebirth\mods\external item descriptions_836319872)

You can manually change the following values in the main.lua of the mod to true:

EID.isMultiplayer = false -- Used to color P1's highlight/outline indicators (single player just uses white)
EID.isOnlineMultiplayer = false -- Set to true to disable code functions that might cause desyncs

EID.isMultiplayer = true -- Used to color P1's highlight/outline indicators (single player just uses white)
EID.isOnlineMultiplayer = true -- Set to true to disable code functions that might cause desyncs

https://steamproxy.com/sharedfiles/filedetails/?id=836319872
https://steamproxy.com/sharedfiles/filedetails/?id=2635267643
https://steamproxy.com/sharedfiles/filedetails/?id=2489006943

If you want, feel free to add me so we can beat all the evil into the unknown depths below (or get powned together)