I bet you didn’t know this was possible, right?
So here’s some backstory:
Years ago I was thinking about how annoying it is that I can’t store save files for other games in Steam; As well as technically arbitrary files like Mods. Steam’s API is pretty restrictive, at least on the client, for what files can be stored where. Files have to be in specific folders, specified by the developer of the game, and so on. It’s not incredibly useful honestly, other than for that specific game.
But… That is really only a limitation on the client. If you’re interacting with the API more directly, you can just upload just about anything. Normally Steam Cloud Sync is handled by the Steam Client itself, which is why that limitation exists - As a developer, you don’t have to specifically interact with Steam to get files uploaded - you just tell Steam where the files are and it takes care of the rest. But with the API, that limitation doesn’t exist, and you can, with no effort other than owning the game, from your own application, claim to be any game you want, as long as the user owns it, and as long as that game has Cloud Save, you have storage available.
Of course, some games have more storage than others - I leave it to the community to figure out what game to buy that has 93 GB of storage space and you don’t often play - Keep in mind that if you download that game, Steam will also download your entire Cloud Saves folder, which in this case would include ALL of your data.
Limitations:
Based on some limited research, from what I could find, Steam’s Cloud API has the following limitations (These are, largely, undocumented at least publically:)
- 93GB Cloud Save Storage per Game, Maximum (Maybe Fungable? The default seems to be 93MB so it’s possible this is just someone adding some zeros and it worked; but nobody has deliberately gone bigger)
- 100MB per File is an Ideal Limit, but above 250MB the back end for the API will start to hate you
- Possible Limit of 10,000 Files per Cloud Save
- GameMaker’s SteamWorks Integration says the defualt Quota is 1GB, but I’m not sure of that.
What we know that we do not know:
- There is no publicly documented upper limit from Valve.
- Developers can set quotas at least into the multi-gigabyte range.
- Real-world observed quotas reach roughly 93 GB.
- The file-count limit appears to go to at least 10,000 files.
Downsides:
So with that all out of the day lets go over some potential downsides:
- This is very unsupported by Valve.
- You could potentially get Banned for doing this!
- Caveat: I am not aware of any Bans for this
- Your files could go poof. Your game of choice could change their API and break your storage
- You can’t sync files while playing games on Steam – To impersonate a game, you have to pretend to be that game - And it has to be “running”.
Notes:
- There is no ‘Game’ on Steam that is explicitly for this purpose, suggesting either this is somehow a novel idea or Valve blocks the release of software intended to use Cloud Save for File Storage on Steam.
- Just because nobody has been banned for this publically, doesn’t mean it’s safe. I want to reiterate this: You COULD be banned. I’m not sure if this is a good idea.
Implementation:
There are two ways to implement this imho. In all scenarios you do need to use the SteamWorks API.
The first way would be to create a fuse filesystem that maps to your given Game(s) Cloud Save, during startup grabbing a list of files. I’d suggest maybe using a json file with the files you’re actually storing to prevent mixing in actual save data, and use that for presentation, perhaps with occasional update checking in case of more than device doing sync.
The second way would be to be create tool that can upload/download files on demand. I think this could be particularly compelling for EG EmuDecky users, as it would allow you to store and retrieve all of your Emulated Games Saves into the Steam Cloud as needed.
I’d be interested to see what people think of this, and especially if anyone makes an implementation. I think I’m going to try this out myself, specifically option two, for Emudeck.
If you pick a large enough game, with enough storage, you could theortically store your ROM’s in there too, but honestly I’d hesitate to recommend that - It’d DEFINITLY be against Valve’s TOS for uploading copyrighted material, if nothing else, even though you’re the only possible recipient.
Known Implementations:
Last Updated: May 9, 2026
| Implementation | URL | Usable | Demand or Sync |
|---|---|---|---|
| None | https://github.com | No | Neither |
Feel free to poke me over on Mastodon if you wanna talk about this post, have an implementation (I’ll add it above), or what have you!