SSBU Arena

Super Smash Bros. Ultimate on PC, built for competitive online play.

Rollback netcode through a relay that never shows your address to anyone, a competitive 1v1 mode, and one small launcher that sets everything up and keeps it up to date.

Download for Windows · Website · How rollback works · Build from source

[!IMPORTANT] This repository contains no game code, no game assets, no keys and no firmware. You need your own legally obtained copy of the game (13.0.4 or 13.0.5). Everything derived from it is built on your PC, from your copy, and never leaves it.

[!NOTE] SSBU Arena is based on OpenSmash-Ultimate by Denkishi and its contributors: the static recompilation, the runtime that replaces the console, the Vulkan renderer and the rollback snapshot ring come from there. Arena started as a fork of it and is now developed on its own. See Credits.

Get started

You need
Windows 10 or 11, 64-bit	A graphics card with a Vulkan 1.3 driver
Your own copy of the game	Update 13.0.4 or 13.0.5, with the keys and firmware from your own console. The setup finds them in the folders of the usual emulators
About 25 GB free	The game unpacked from your copy and the files built from it
About 20 minutes, once	The first setup builds the game for your PC. Updates afterwards take a few minutes

1. Download SSBU-Arena.exe and save it in a new, empty folder: SSBU Arena installs itself next to it.
2. Open it. The setup checks your PC, finds your game, keys and firmware, and builds Ultimate for your PC.
3. Create your account on ssbuarena.com and sign in from the launcher to play online. Then press Play.

[!TIP] Windows says "Windows protected your PC"? SSBU Arena is a new app, so SmartScreen asks before its first start: choose More info, then Run anyway. If a double-click does nothing, right-click SSBU-Arena.exe > Properties > tick Unblock > OK, and open it again. It never needs to run as administrator.

Every time it starts, the launcher checks for a new release and updates itself and the game in place. Your saves and settings stay.

What Arena adds

	Feature	State
🌐	Rollback netcode online: the game's own Local Wireless rooms played over the internet, with rollback instead of the game's delay-based netcode	Live
🛡️	Relay-only server (tools/net/rb_lobby.c): every packet goes through the server, no hole punching, no player ever learns another player's IP	Live
📶	Ping on screen in every online match, next to each player	Live
🏆	Competitive mode: the six legal stages (Battlefield, Small Battlefield, Final Destination, Pokémon Stadium 2, Smashville, Town and City), no items, no Final Smash meter, no hazards	Live
🖥️	SSBU Arena launcher (tools/launcher/arena): one-file download, guided setup, automatic updates, account sign-in, controllers, video and audio settings, shader preparation	Live
🎮	Arena main menu: Smash, Online LDN, Battle Arena, Online Matchmaking, Settings and Exit, with an in-game settings menu	Live
💾	Light archive: only what competitive 1v1 needs (8.8 of 16.4 GB)	Live
👥	Friends, invites and Arena lobbies	In development
📈	Automatic ranked 1v1 with skill-based ratings	In development

The full roadmap is on ssbuarena.com/project.

How it works

The game's AArch64 code is translated to C ahead of time and compiled into a native Windows program: no emulation. The console's system libraries, graphics, audio, input and files are re-implemented, and the picture is drawn with Vulkan.

your copy --> tools/extract --> main executable, SDK, script modules, data
                 |
        tools/lifter (recomp.py)     AArch64 -> C, one C function per game function
                 |
        clang --> game DLL + one DLL per script module
                 |
        runtime/                      what the console provided, re-implemented (threads, files, audio, input,
                                      movies, fonts, network), NVN graphics on Vulkan,
                                      rollback (r1_*.c, rb_*.c) and the online layer (net_relay.c)

Releases ship the launcher and a prebuilt runtime (our code only, audited for game content by scripts/make_release.py); the game itself is always built on the player's PC.

Build from source

Everything the launcher does can be done by hand:

git clone https://github.com/ssbuarena/ssbu-arena

Then follow BUILDING.md (Linux: BUILDING_LINUX.md, macOS: BUILDING_MAC.md). Contributions are welcome: read CONTRIBUTING.md first.

FAQ

Is this legal? The repository contains no game code, assets, keys or firmware, and does not help anyone obtain them. You build the program on your PC from a copy of the game you own. This is not legal advice; laws differ by country.

Does it include the game? No. Not the game, not the keys, not the firmware, and no links to them.

Is my IP shared with the other player? No. Every online packet goes through the Arena server; the other player only sees a virtual address of the server's network.

What data does SSBU Arena collect? Only what an account and online play need. See the privacy policy.

Credits

SSBU Arena is made by Acid236: online play through the relay server, rollback netcode online, the ping overlay, the competitive mode and light archive, the Arena menu and the launcher.

It exists because of OpenSmash-Ultimate / ssbu-recomp. Thank you to Denkishi, who created it and wrote most of it, and to its contributors: Stephen Jayakar, xtlg511, v1Ta44, Frank Fly, Victor Navega and jfb112697. The full history of their work is kept in this repository's git history. Details, and the open-source projects both projects build on, are in CREDITS.md.

Legal and license

SSBU Arena is not affiliated with, endorsed or sponsored by Nintendo, Bandai Namco or Sora Ltd. Super Smash Bros. and Nintendo Switch are trademarks of their owners and are named only to say what the software works with. The repository contains no copyrighted game data, no console keys and no firmware, and does not help anyone obtain them. You must own the game and dump it yourself. No Nintendo logos or artwork are used.

Licensed under the GNU General Public License, version 3 or later, the same as OpenSmash-Ultimate (see LICENSE). Files keep their original copyright and license notices.