RetroArch
Netplay across dozens of emulation cores
Installation
Download RetroArch
Go to retroarch.com → Platforms and download the installer for your OS. On Windows, the installer is recommended over the portable build.
Install cores
Open RetroArch → Main Menu → Online Updater → Core Downloader. Install the cores you need (e.g. Snes9x for SNES, mGBA for GBA, Mupen64Plus-Next for N64).
Update assets and databases
Go to Online Updater → Update Assets, Update Core Info Files, Update Databases, and Update Cheats. Keeping these up to date prevents issues.
Netplay Setup
Enable relay server
Go to Settings → Netplay → Use Relay Server and set it to "ON". This routes your connection through a Libretro relay which helps bypass NAT.
Host a game
Launch a game with the desired core → then go to Main Menu → Netplay → Host Netplay Game. A room will appear on the RetroArch lobby (visible on the netplay browser).
Join a game
Go to Main Menu → Netplay → Refresh Netplay LAN List (for local) or connect to a room from the lobby. Alternatively, enter a host IP directly via "Connect to a Netplay Host".
Spectate mode
To spectate without playing, enable "Spectate Mode" in Netplay settings before joining. You'll see the game but won't control anything.
Netplay buffer
Under Settings → Netplay, set "Netplay Input Latency Frames Min/Max" based on ping. For LAN: 0/0. For 60 ms ping: 3/4. Higher values reduce hitching at the cost of input delay.
Core-specific Notes
SNES — Snes9x
Snes9x is the recommended SNES core for netplay. Both players must use the same Snes9x version. Avoid bsnes for netplay — it's more accurate but heavier and prone to sync issues.
N64 — Mupen64Plus-Next
Use Mupen64Plus-Next for N64 netplay. Set the video plugin to glN64 or Parallel-RDP. Both players should use identical plugin settings to avoid desyncs.
GBA — mGBA
mGBA supports netplay in RetroArch. Note that GBA games were designed for link cable — not all games have meaningful multiplayer.
Arcade — FinalBurn Neo
FinalBurn Neo (FBNeo) is the best arcade core for netplay. Use the same ROM set version (FBNeo maintains its own updated romset).
Troubleshooting
Desyncs
Ensure both players use identical: core version, ROM (same MD5), core options, and no cheats enabled. Save states from single-player are not compatible with netplay sessions.
Cannot connect without relay
If relay is unavailable or slow, port forward port 55435 (TCP and UDP) on your router. Share your public IP with your opponent.
Audio crackling
Go to Settings → Audio and increase the audio latency to 64 ms or higher. Alternatively, switch the audio driver to wasapi (Windows) or alsa (Linux).
Ready to play?
Find active sessions on NetplayFinder.