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Steam Workshop addons are the heart of Garry’s Mod — maps, weapons, playermodels, gamemodes, and tools all come from the Workshop. This guide shows you how to mount a Workshop collection on your Wasabi Hosting server, make clients download the content automatically, and keep everything up to date.

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How It Works

Server-side Workshop content involves three pieces:
  1. A Workshop collection — a list of addons on Steam that your server should load.
  2. A Steam Web API key — lets your server query the Workshop and download the collection.
  3. resource.AddWorkshop — a small Lua script that tells joining players which addons to download so they don’t see missing textures and errors.

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Step 1: Create a Workshop Collection

1

Open the GMod Workshop

Go to the Garry’s Mod Steam Workshop in your browser and sign in to Steam.
2

Create a collection

Click Browse → Collections → Create Collection. Give it a name, set visibility to Public (the server can’t read private collections), and save it.
3

Add addons

Browse the Workshop and click Add to Collection on each addon you want. Maps, weapons, and playermodels are all added the same way.
4

Copy the collection ID

Open your collection page and copy the number at the end of the URL — for example, in steamcommunity.com/sharedfiles/filedetails/?id=1234567890 the collection ID is 1234567890.

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Step 2: Get a Steam Web API Key

Your server needs an API key to download Workshop content:
  1. Visit steamcommunity.com/dev/apikey while logged in to Steam.
  2. Enter any domain name (e.g. wasabihosting.com — it isn’t validated for this use).
  3. Agree to the terms and click Register.
  4. Copy the key that’s displayed.
Treat your API key like a password — anyone with it can act on the Workshop through your Steam account’s API access. Never share it publicly or commit it to public files.

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Step 3: Add the Startup Parameters

In the Game Panel, open your server’s Startup tab and add these parameters (the panel may provide dedicated fields for them): 
+host_workshop_collection 1234567890 -authkey YOURAPIKEY
  • +host_workshop_collection — your collection ID from Step 1.
  • -authkey — your Steam Web API key from Step 2.
Restart the server. On boot, the console will show it downloading and mounting each addon in the collection — the first start after adding a large collection can take several minutes.

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Step 4: Make Clients Download the Content

Mounting the collection only affects the server. Without one more step, players who don’t own the addons will see missing textures (pink/black checkers) and ERROR models. Fix this with resource.AddWorkshop:
1

Create the script

Using the File Manager or SFTP (File Management), create a new file at:
garrysmod/lua/autorun/server/workshop.lua
2

Add one line per addon

Each line uses the addon’s Workshop ID (from its Workshop page URL — not the collection ID):
-- lua/autorun/server/workshop.lua
resource.AddWorkshop("2818480138") -- Example: a custom map
resource.AddWorkshop("111412589")  -- Example: a weapon pack
resource.AddWorkshop("104603291")  -- Example: playermodels
3

Restart and test

Restart the server, then join with a client that doesn’t have the addons installed — you should see “Downloading…” entries on the loading screen.
Only add content that players actually need to see (maps, models, textures, sounds). Server-side-only addons like admin mods don’t need resource.AddWorkshop — skipping them keeps join times short.

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Alternative: Legacy Addons Folder

Some content isn’t on the Workshop (private scripts, purchased addons from marketplaces, extracted legacy addons). These go directly into the addons folder:
  1. Open the File Manager and navigate to garrysmod/addons/.
  2. Upload the addon folder (it should contain files like addon.json or subfolders such as lua/, models/, materials/).
  3. Restart the server.
Workshop .gma files can also be placed in garrysmod/addons/ and the server will mount them directly. Folder-based addons must keep the correct internal structure — an addon nested one folder too deep won’t load.

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Keeping Addons Updated

  • Workshop collection addons update automatically — the server re-checks the collection on each restart, so a simple restart pulls the latest versions.
  • Adding/removing addons — edit the collection on Steam, then restart the server. Remember to update workshop.lua if you added client-visible content.
  • Legacy folder addons never auto-update; re-upload new versions manually.
  • Schedule a nightly restart via the panel’s Schedules feature to keep content fresh and memory usage low.

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Performance Considerations

Every mounted addon costs startup time, memory, and often tickrate. Symptoms of addon bloat include long join times, low FPS for everyone, and server lag spikes. Audit your collection regularly and remove what you don’t use — then see the Server Optimization guide for deeper tuning. Before major addon overhauls, take a backup so you can roll back a broken configuration in one click.

Host your addon-packed server with Wasabi

Garry’s Mod hosting from €12.50/month on Ryzen 7950X3D/9950X hardware — fast NVMe storage means even big collections mount quickly.