Arma 3: STEAMWORKSquery

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Revision as of 20:31, 18 June 2014 by Dwarden (talk | contribs) (Client)
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Available functionality

Steam API provides an ability to register a game server to Steam master server for player to find it and get it's ip and port,
that is later used by the client to directly connect to the game server.
In order to players find/select server they want the game server has to send an information about itself to Steam master server.
This information could be used to filter out server the player is not interested in.

Server query

Available means to set information about the server (what can be set to Steam master server and be retrieved by clients from Steam).
Values set by (marked by the orange italic underlined text  ) functions are accessible by the clients, rest is used only by the Steam master server.

Main Table

Function/variable type max. size description what value is set by the Arma3 server
SteamGameServer_Init     Initialize steam server object, and set server properties which may not be changed.

Sets the version of the server.

To set version of the server
SetProduct() string   Game product identifier. Identifies to what Steam game the session belongs. constant string "Arma3" for all sessions
SetGameDescription() string 64 chars Description of the game.  

This is a required field and is displayed in the steam server browser

mission name
SetModDir() string 32 chars If your game is a "mod," pass the string that identifies it. constant string "Arma3" for all sessions
SetDedicatedServer() bool true/false Is this is a dedicated server?  The default value is false. set to true if server is dedicated, false otherwise
SetMaxPlayerCount int   Max player count that will be reported to server browser and client queries maximum possible number of players in the mission
SetBotPlayerCount int   Number of bots.  Default value is zero not used
SetServerName string 64 chars Set the name of server as it will appear in the server browser game session name
SetMapName string 32 chars Set name of map to report in the server browser name of the map (altis, stratis...)
SetPasswordProtected bool true/false If session is password protected set to true if server is password protected
SetSpectatorPort int   Spectator server. The default value is zero, meaning the service is not used. not used
SetSpectatorServerName char 32 chars Name of the spectator server.  (Only used if spectator port is nonzero.) not used
SetGameTags char 128 chars Sets a string defining the "gametags" for this server, this is optional,

but if it is set it allows users to

filter in the matchmaking/server-browser interfaces based on the value

used for various parameters, described below.
SetGameData char 2048 chars Sets a string defining the "gamedata" for this server, this is optional,

but if it is set it allows users

to filter in the matchmaking/server-browser interfaces based on the valuedon't set this unless it actually changes,

it's only uploaded to the master once (when acknowledged)

not used
SetRegion char   Region identifier.  

This is an optional field, the default value is empty, meaning the "world" region

not used
SetKeyValue char, char 127 chars per pair

max 1300 for all pairs

sets key/value pair for the session.

All pairs can't take more than 1300 characters (about 11 pairs max).

used for storing:
  • GLoadedContentHash (1 pair), 
  • modHashes (2 pairs), 
  • modNames (2 pairs), 
  • sigNames (2 pairs), 
  • param1 (1 pair), 
  • param2 (1 pair), 
  • timeLeft (1 pair), 
  • country (1 pair).

SetGameTags in detail

Arma 3 is currently using SetGameTags parameter to pass multiple information about the session. 
All these parameters are encoded into the single string, each parameters is separated by the colon. 


  • BattleEye - bool flag
  • EqualModRequired - bool flag
  • RequiredVersion - value
  • RequiredBuildNo - value
  • GameType - int
  • ServerState - int
  • Dedicated - bool flag
  • Lock - bool flag
  • VerifySingnatures - bool flag
  • Language
  • Difficulty 
  • Platform - windows/linux
  • LongLat - position of the server


first character of each tag defines it's type, rest is a value.

Value in the string identifier value meaning
bt, b true BattleEye 
r120, r 1.20 RequiredVersion
n0, n 0 RequiredBuildNo
s1, s 1 ServerState
i2, i 2 Difficulty
mf, m false EqualModRequired
lf, l false Lock
vt, v true VerifySignatures
dt, d true Dedicated
ttdm t tdm GameType
g65545, g 65545 Language
c0-52, c long.=0 lat.=52 LongLat
pw p Windows Platform


gameTags = bt,r120,n0,s1,i2,mf,lf,vt,dt,ttdm,g65545,c0-52,pw,

Comparsion of the current STEAMWORKS implementation to GameSpy

GS param Steam equivalent Description
"numteams" none in GS always set to 0
"password" SetPasswordProtected  
"param1" SetKeyValue  
"param2" SetKeyValue  
"equalModRequired" SetGameTags  
"reqSecureId" none A3 no longer uses cd keys
"dedicated" SetGameTags  
"sv_battleye" SetGameTags  
"currentVersion" SteamGameServer_Init  
"requiredVersion" SetGameTags  
"difficulty" SetGameTags  
"verifySignatures" SetGameTags  
"numplayers" none this value is update by Steam automatically
"maxplayers" SetMaxPlayerCount  
"language" SetGameTags  
"hash" SetKeyValue  
"gameState" SetGameTags  now under serverState
"reqBuild" SetGameTags  
"mod" SetKeyValue  
"mapname" SetMapName  
"gametype" SetGameTags  
"mission" SetGameDescription  
"gamename" SetProduct()  
"signatures" SetKeyValue  
"modhash" SetKeyValue  
"gamemode" none  
"platform" SetGameTags  

Additional details


Read details about (customizable) STEAM ports on server.


For hosting MP game locally (so called listen server) behind NAT please ensure the default STEAM ports are forwarded and open!

When you have issues with the in-game server browser then try to use the STEAM client server browser instead.
STEAM > menu View > Servers > at bottom in filters choose game "Arma 3" > pick server and play
note: Try to join password protected server via STEAM client's server browser returns wrong password, will be fixed next patch/hotfix