- "Your own custom apocalypse. Discover and download new maps, Add-ons, Mutations and more! Want to try your hand at modding or want to upload your mod to Steam? Click here to learn more."
- ―Workshop descriptionThe Steam Workshop is a database for uploading to user-created content available on Steam. The only game in the Left 4 Dead series with Steam Workshop support is Left 4 Dead 2.
It was introduced after the February 7, 2013 update along with most other games such as Counter-Strike: Global Offensive, Team Fortress 2 and notably Garry's Mod.
The Workshop is split into various categories, such as Custom Campaigns, weapon/skin mods, sound mods, UI mods, and other kinds of modifications. These can be downloaded by clicking "subscribe" and deleted by clicking "unsubscribe".
This made acquiring addons easier since it automatically updates the addon when needed, unlike manually placing one. Furthermore, if a user has multiple devices, it will download the mod to any that the user downloads Left 4 Dead 2 to, so long as they use the same Steam account.
On the downside, it does require a constant network connection to use the addons, though the game does not need a connection to play offline.
One can use multiple tags to search needed items. The items can also be sorted by the number of subscribers, popularity, the date of release over a specific time period. One can also add an item to their Favorites by clicking on the heart sign in order to easily find it later. Users may assemble multiple add-ons in Collections, so the others can instantly subscribe to all the add-ons from these at once.
- Skin mods (Usually weapon worldmodel and infected skins) can cause problems when playing on local servers if the host server's CVAR of "sv_consistency" is set to 1. It rarely causes issues on official servers, though one can still encounter this should the skin mod exceed the allowed size. Some custom skins (especialy infected mods) can prevent others from joining on local server (as the game tries to download the said skin) unless guests' "downloading custom content" is set to off.
- Usually, if a PC has multiple users logged on it and should another user have launched Left 4 Dead 2 on the same PC, it may require a re-download of all mods, even if it's already in the folder.
- As of November 1, 2018 update, Steam Workshop mods were disabled in the official servers in Versus, Realism Versus, and Scavenge Modes for balancing reasons, most likely regards to Weapon Scripts.
- However, it is possible to bypass this by editing addonconfig.txt file and changing every "1" to "0" in it. Sadly, this will only allow mods to work if player who did this is the host (you can't use mods in servers/games where you are not the host, server/host must have mods enabled) and thus you can't join random game (which obviously still can) and except mods to work. Alternatively, the mods have to be placed traditionally much like in L4D1 by placing any mods inside the separate folder and place it onto the root of the Left 4 Dead 2 directory and then create a new line in the gameinfo.txt file for the corresponding mod folder that the user created in the root of the Left 4 Dead 2 directory. This method can be followed in this guide.
- By March 2019, Left 4 Dead: Survivors (LEFT 4 DEAD -生存者たち-) was leaked online, and since then, fans ported to Left 4 Dead 2 most of the game's original assets through the Steam Workshop.