What should I use for testing Steam multiplayer, Spacewar or real AppID?

[Kiwano341]

Hi folks!
I wonder what the best way to go about testing the steam multiplayer functionalities for a game from multiple steam accounts? From what I have found there are at least 2 ways of going about it:

Option A, Quick loop with Spacewar (AppID 480):

Creating a second Steam account and friending it from my main account.

Running Steam on two separate machines/VMs (Steam won’t allow two logins in one session on the same box).

Exporting a debug build (Windows) and copying the whole export folder to both machines.

In that folder, adding steam_appid.txt with:
480 (Keeping my normal Steam code, this just enables overlay + networking via Spacewar.)

Ensuring steam_api64.dll (and any GodotSteam/Steamworks deps) sit next to the EXE.

Logging into Steam on both accounts (online, overlay enabled) and running the EXE directly (not from the library). Shift+Tab should bring up the overlay.

On Player A, create a lobby and Invite → Player B accepts via overlay and joins.

Verifying callbacks (lobby_created, lobby_joined), avatars/names, and my RPC flow.

Option B, Test against my real Steamworks app:

Changing the steam_appid.txt to my actual AppID.

Adding the second account as a playtester or co-dev in Steamworks.

Either keep running the EXE with steam_appid.txt, or uploading a build to Steamworks and have both accounts install via Playtest/beta branch.

Do these routes work well for Steam MP testing, or have you found a more suiting approach?

[Gramps]

Hey there! Those are pretty standard routes, as far as I know. Most people have been employing separate machines or VMs. There was a pretty weird method someone shared about somehow spoofing or splitting the Steam connections to work on one account. As far as I could tell, it might only work on Windows and I actually don't remember where it was shared. I will try to look for it later today and link it if I can find it.

[Kiwano341]

Ok, thanks!