Posted by squidleon 15 hours ago
What it does today: - Full packet layer for the classic UO client (login, movement, items, mobiles) - Lua scripting for item behaviors (double-click a potion, open a door — all defined in Lua, no C# recompile) - Spatial world partitioned into sectors with delta sync (only sends packets for new sectors when crossing boundaries) - Snapshot-based persistence with MessagePack - Source generators for automatic DI wiring, packet handler registration, and Lua module exposure - NativeAOT support — the server compiles to a single native binary - Embedded HTTP admin API + React management UI - Auto-generated doors from map statics (same algorithm as ModernUO/RunUO)
Tech stack: .NET 10, NativeAOT, NLua, MessagePack, DryIoc, Kestrel
What's missing: Combat, skills, weather integration, NPC AI. This is still early — the focus so far has been on getting the architecture right so adding those systems doesn't require rewiring everything.
Why not just use ModernUO/RunUO? Those are mature and battle-tested. I started this because I wanted to rethink the architecture from scratch: strict network/domain separation, event-driven game loop, no inheritance-heavy item hierarchies, and Lua for rapid iteration on game logic without recompiling.
Obligatory nitpicky aside, a time-honored tradition of HN:
I've long been irritated by the use of the term "server emulator" in gaming contexts. Technically these projects are just reimplementations of a proprietary networking protocol. Nobody calls Samba a "server emulator" because it reimplements the Windows file sharing protocol, because Samba isn't "emulating" anything from the perspective of the traditional definition of "emulator" in computer science.
But for some reason, I guess because "emulator" has colloquially been redefined by non-CS nerd gamer normies as a term for software that lets you play proprietary games on platforms they were not designed for, we have ended up in this new status quo where the term's definition has expanded in this game of telephone way that annoys mainly me and not many other people.
And what's kinda funny is I say that it is a "new" status quo, but it's not even that new. I recall, what, like 20 years ago now I was in an edit war on Wikipedia fighting with people over the "server emulator" article, insisting that the term was technically inaccurate and should not be used. Unsurprisingly in retrospect, I lost that edit war.
Nowadays the whole thing feels like my first "old man yells at cloud" moment, of which I'm sure I'll experience more as I age. I certainly do find new slang introduced by gen Z like "he got the riz!" to be quite cringey, so it looks like I'm well on my way to getting crotchety and terrible about the natural evolution of language! ;)
That said, I'll take the nitpick as a compliment :) means you actually read the project description. Thanks for the kind words! > other example Mangos is "Wow emualtor"
And funny you mention Mangos — the WoW emulation scene was a huge inspiration for UO server development back in the day. Different game, same passion for reverse-engineering and rebuilding these worlds. The
community-driven server scene is one of the best things about MMO gaming in general.
Thanks for the kind words and good luck with your WoW adventures! :*!I think the distinction is a lot greyer than the black/white you propose.
The very first popular online games used servers mostly to redistribute (and maybe time sync) packets from clients. There is no standard way to to do that. Player-created servers did their best to emulate the official servers logic but it was indeed impossible to replicate it perfectly.
e.g. when breaking up large maps into sectors, the official server might broadcast your location and projectiles X units away and emulators would broadcast it X + 500 units away, which could have an impact on gameplay.
Emulator feels fitting when there is no official server spec to reimplement.
edit: emulator also feels appropriate where servers are responsible for NPC activity or quest-like mechanics. This goes beyond implementing a network protocol. The gameplay is massively impacted.
You're not wrong that "server emulator" is a generically correct use of the term emulation, in the same sense that it is a correct use of the word for someone to say they emulate a fashion sense of a celebrity they like in their own wardrobe.
But in computer science, strictly speaking, the original definition of emulator was more strict. It was about things like emulating processor architecture A so as to execute programs written for it on processor architecture B.
And part of why expanding the definition to include "server emulators" annoys me is why has this definition expansion occurred only in gaming contexts? If a free UO server is a "server emulator" then why is Samba not also a server emulator? The lack of consistency is irritating to me, and it only happened because gamers like the term emulator, not due to any kind of rigorous computer sciencey reason.
This is interesting to me, if only because it's such a natural bit of slang. Given that it's a shortened form of "charisma", this one just Makes Sense to me! I figure it'd be incredibly cringe for me to use at my age, but it's a good term IMO.
There's been research by linguists (John McWhorter comes to mind) analyzing this phenomenon and it basically just comes down to the fact that as we age, we get more set in our ways, so the linguistic innovations that younger people do just have a tendency to annoy us, even when they logically follow or are objectively useful.
I try not to let it bother me, because it's irrational to feel that way, but it just does lol
I don't know if there are "family-friendly" presets for such things, but so far Copilot has been reasonably helpful at helping me along -- I just don't have it all working yet. If you have any resources you come across, I would be interested in comparing notes. :)
They've reworked a lot of systems and it's basically 100x better than original UO.
There are several systems in place, which original devs wouldn't even dream of and saying that, official Ultima Online is still running. :D
It's PvP server, but with balanced PvP which really works for everyone. Not like original devs, they just dropped PvP because cookie-cutter players cried.
Personally though, I feel they've overengineered it a bit. So many custom systems layered on top that it starts to feel more like WoW with UO graphics than actual UO. The original charm was in the simplicity you, a sword, and a world that didn't care about your feelings. But that's just my taste, and clearly thousands of players disagree with me, so what do I know. And yes, the fact that official UO is still running in 2026 is both beautiful and insane
I recently tried https://www.classicuo.eu/ ClassicUO, and the nostalgia was incredible. Granted it is not playable, but there is something about that experience that all of the assistants, hotkeys, etc. fail to capture.
Dead on.
I spent many many hours in UO when I was young.
It was so great playing in some shards with hundreds of real persons.
"Who owns the UO IP now and how litigious are they?"
Ultima Online launched in September 1997. The first "offline emulator" launched in October. Emulators became playable by mid 1998. https://www.uox3.org/history/timeline.txt