Play Retro Games Online with a Friend Using RetroArch Netplay

RetroArch Netplay keeps two copies of the same emulator in lockstep and uses rollback to hide lag. Both players need the same core and the same game file, and RetroArch's relay server avoids opening ports on your router.

Mission steps

1. Install a RetroArch system

   Use RetroPie or Lakka on the Pi; your friend can use RetroArch on a PC, another Pi or a laptop.

2. Match everything

   Both sides must use the same core (for example Snes9x) and the exact same game file, from a game you own or homebrew.

3. Host the game

   In RetroArch, load the game, go to Netplay → Host and enable the relay server so your friend can join without port forwarding.

4. Join

   Your friend opens Netplay → Refresh Room List and joins your room, or connects directly to your IP.

5. Reduce lag

   Wire both machines with Ethernet and pick 8- and 16-bit systems first; they sync best.

Code

# From the command line (RetroPie core path shown)
# Host:
retroarch -L /opt/retropie/libretrocores/lr-snes9x/snes9x_libretro.so --host ~/RetroPie/roms/snes/mygame.sfc
# Friend on the same LAN or with port 55435 forwarded:
retroarch -L /path/to/snes9x_libretro.so --connect 192.168.1.40 ~/roms/mygame.sfc

Tip: test every script on the bench before installing it in a moving machine.

Questions