Mods is officially supported by D2R, but I don’t think Blizzard gave a clear stance on what kind of things are allowed and what are not. E.g.
- Are we allowed to use pure visual mods like showing stats range, showing monster level of a map or changing the icon of the runes to display rune # and names.
- Are we allowed to use loot filters that hides irrelevant loot like bolts and showing an exclamation mark when an important loot drops (#20+ runes or a charm)?
3.etc.
I saw there are some arguments about mods and it seems a popular opinion is 1 is OK and 2 is bannable. But this is all pure speculation. A lot of players and streamers using loot filters are not getting banned and the players who played the game legitimately are getting a disadvantage.
I think it’s time for Blizzard to give a complete blue post on the details of mods. It’s ridiculous that the game adds official support for mods but not allow any of the mods to be used. (Blizzard policy is always unless I authorize something explicitly, players are not allowed to use it).
As long as you keep them in single player and only used authorized modding techniques (everything except code editing and code injection are allowed I think) you should be good to go.
The folks over at the Phrozen Keep know more and that would be a good place to start.
I hope TCP/IP or another alternative LAN functionality is (re)implemented in the future to allow modded multiplayer (among other benefits).
I would stay away from any modding online to keep your account safe.
Anything that has a hook to read your RAM is 
adjusting any game files for online play is
This kind of stuff is in their TOS.
The support for mods was intended for single player only, and there are a ton of them. This has been well known to be the case and communicated before the game came out.
I’d personally love a loot filter though. Hopefully they’ll add support with the next ladder season. Things will continue to change as we progress into the game, and maybe bigger changes will happen with MS taking over, as they’re known for private server use and allowing players to mod games a lot more than Blizzard allows.
I actually saw streamers using loot filter in online game. I don’t think Blizzard has enough manpower in D2R to enforce anything. So players who doesn’t “cheat" end up having a disadvantage. If that’s the case, I hope they could just open up loot filters either ingame or by mods.
That should kind of be obvious lol. No mods of any kind online. Do so at your own risk. Their stance has been crystal clear on this for a long time. Blizzard also tends to ban in waves when people least expect it, so just because somebody is getting away with something doesn’t mean they are getting away with it for long.
Wait, what? Is there an API like in WoW addons? We can write our own mods for D2R?!