How to Add Workshop Addons to a Garry's Mod Server

Make the collection

1. On the Garry's Mod Workshop, open Collections and create one (it can be public or unlisted).
2. Add the addons, maps and gamemodes your server needs. A gamemode is an addon like any other.
3. Copy the number at the end of the collection's link: that is its ID.

Give it to the server

The launch option is +host_workshop_collection <id>. On Flux, paste the ID into Workshop Collection in Deployment Settings and save; the server redeploys and downloads it. No Steam Web API key is needed: our test server downloaded a 21-addon collection without one.

The server checks the collection on every start, so adding an addon to the collection on Steam and restarting the server is enough: there is no list to edit on the server side.

What players download

Players joining the server get the collection's addons from Steam, which is fast. Content that is not on the Workshop (a custom model pack, a map you built) has to come from the server itself or a FastDL web server: put it in the server's addons folder with the Files tab and set sv_downloadurl if you have one.

Disk space

Addons are cached beside the server. Our 21-addon test collection took 236 MB; a roleplay collection with player models, vehicles and custom maps can run to several gigabytes. Each plan's storage is listed on the pricing page, and the Hardware tab adds more.