SandTogether — Sandustry Co-op Mod

SandTogether is a community-built co-op mod for Sandustry. It adds multiplayer to a base game that ships as single-player only — there is no official co-op mode and Lantto Games has not announced native multiplayer for Early Access. SandTogether lives on the Steam Workshop and runs through the Fluxloader loader, so installation mirrors Custom Maps and Fluxloader Install. This page tracks what the mod is, how to install it, and what changes when you stop playing solo.\n\n## What SandTogether is\n\nSandTogether is a Workshop mod, not a developer feature. Concretely:\n\n- Unofficial. Lantto Games and Hooded Horse have not endorsed or shipped it. Treat its existence as a community contribution, not a roadmap promise.\n- Workshop-hosted. It is published through Steam Workshop, the same channel used by Custom Maps.\n- Loader-routed. It requires Fluxloader to be installed first. The mod sits inside the Fluxloader Mods folder and is toggled from the launcher menu.\n- Multiplayer layer. It connects two or more players into a single shared Sandustry world. The exact party size, host model, and session rules are defined by the mod build; check the Workshop description before inviting your second player.\n\nIf Hooded Horse announces first-party co-op later, this page will defer to official news on the Updates Hub. Until then, every co-op session you run goes through this mod.\n\n## Why the base game is single-player\n\nThe retail build — Steam app 2764460, GOG, Microsoft Store, PC Game Pass (desktop only) — is sold and documented as single-player. The release notes, the EA Launch snapshot, and the Early Access Preview all confirm this. There is no matchmaking, no cross-play, and no hosted-session browser in the vanilla game.\n\nIf you buy Sandustry expecting co-op, you will be disappointed. SandTogether is the bridge, not the destination.\n\n## Install steps\n\nFollow these in order. Skipping the vanilla-first step is the most common cause of broken sessions.\n\n1. Verify vanilla. Launch Sandustry from Steam/GOG with no mods and confirm you reach the main menu and start a clean save. This isolates any later crash to the mod layer.\n2. Install Fluxloader. Use the Fluxloader Install guide. Note your Fluxloader folder path.\n3. Subscribe to SandTogether on Steam Workshop. The mod is listed in the Sandustry Workshop. Subscribing triggers a Steam download.\n4. Copy or symlink the mod into Fluxloader. Workshop mods typically land in …\\Steam\\steamapps\\workshop\\content\\2764460\\<mod_id>. Either copy the files into the Fluxloader Mods directory or follow the mod readme’s symlink instructions.\n5. Enable SandTogether in Fluxloader. Launch the game through Fluxloader and toggle the mod on.\n6. Restart the game if the loader prompts you to do so.\n7. Host or join. The mod’s menu should expose host/join options. Pass the host’s IP or use the mod’s matchmaker if it ships one.\n8. Test with a friend. Drop into the shared world, place a Shaker together, and confirm both clients see the same pixels. If they desync, see Troubleshooting.\n\nAlways back up your saves before enabling any multiplayer mod.\n\n## What changes in co-op\n\nSharing a factory changes the loop more than you expect:\n\n- Gold is shared. Both players’ Collectors feed the same Research wallet. Spending decisions must be negotiated.\n- Research unlocks once. The Research tree is global. Whoever pays unlocks the node for both players.\n- Slag goes to a single pit. The Kinetic Slag Press is shared; one player can starve the other if they hog the slag pile.\n- Water routing is global. A flooded dig site affects both players. Plan pipes and vents together.\n- Flora and Fluxite are shared. The single Flux Emanator is a contested resource. Decide who owns the botanical wing.\n- Tier 5 save repair still applies. Update 0.5.4 saved your shared factory; the mod layer does not break that, but it does not fix an already broken save either.\n\nThese rules are not “bugs.” They are the natural consequences of turning a solo factory into a shared one. Treat the first session as a sandbox, not a min-max run.\n\n## Balance caveats\n\nSandustry was tuned for one player, one factory, one research tree. Co-op tips the math:\n\n- Double shakers don’t mean double gold. Two players placing Shakers in the same area will saturate the Wet Sand input faster than either can wet sand. Coordinate input belts.\n- Tool sharing beats tool duplication. Two Flamethrowers on the same Slag pile is overkill. Spread out across the factory.\n- Drones conflict. Two players calling Hauler Drones to the same pit creates a queue. Pick distinct haul routes.\n- Puzzle gating breaks. If the map has gated puzzles, two players can solve them twice as fast — or twice as destructively. Read the map rules.\n If your group wants competitive balance, treat co-op as one shared player, not two. The mod multiplies your reach, not your gold.\n\n## Etiquette for shared factories\n\nThe mod is mechanically simple; the social contract is not. Rules of thumb:\n\n- Decide ownership of zones before you build. Who owns the lake, the slag pit, the Flux Emanator? Draw boxes if you have to.\n- Use the same Research priority list. Both players should read Research Priority and agree on the next unlock.\n- Don’t demolish without warning. The Demolisher can wipe a co-player’s section in one tap. Announce removals.\n- Log crashes. If one client crashes, the other should grab main.log (Crashes and Performance) from both machines.\n- Save often. Shared saves are still saves. The 256-tile red-block demolish rule from Update 0.5.4 still applies per player.\n\n## Troubleshooting\n\nMod not in the launcher. Workshop download didn’t finish, or the mod files are not in the Fluxloader Mods folder. Re-subscribe and re-copy.\n\nCrash on co-op join. Mod version mismatch, or one player is on a different game build. Confirm both clients are on v0.5.5 or newer, matching mod version.\n\nDesync between clients. Sand physics differ slightly between versions. Re-host and re-join; if desync persists, fall back to vanilla and post logs.\n\nPerformance collapse. Two players means two simulations. Expect higher CPU and RAM use. 4 GB minimum spec from Release Date and Platforms is the floor; 8 GB recommended for stable co-op.\n\nMod broke after a patch. Sandustry updates change APIs without notice. Wait for the mod author to publish a compatibility update before applying the next official patch.\n\n## Linux and Steam Deck\n\nSandustry ships native Linux support. The mod layer depends on Fluxloader and Steam Workshop. Steam Deck compatibility is plausible but unverified per mod build — test on the Deck’s desktop mode before relying on handheld play. Report Deck-specific issues to the mod author and reference the Steam Deck troubleshooting on Crashes and Performance.\n\n## When official co-op arrives\n\nThe week-one milestone page (100K Sales Milestone) covers the audience signal. If Lantto Games or Hooded Horse announce first-party multiplayer, this wiki will:\n\n- Add an official co-op page under Updates or Review.\n- Reposition SandTogether as a transitional mod.\n- Update the EA Roadmap cross-link.\n- Flag SandTogether as legacy in this page’s nav label.\n\nUntil then, treat SandTogether as the only path to co-op Sandustry.\n\n## Related\n\n- Mods Hub — Fluxloader, custom maps, and the SandTogether workflow.\n- Fluxloader Install — Required base loader.\n- Custom Maps — Same Workshop pattern, solo maps.\n- 100K Sales Milestone — Why co-op exists as a mod right now.\n- EA Roadmap — Whether official multiplayer is planned.\n- Release Date and Platforms — Single-player confirmation.\n- Early Access Preview — Buyer expectations, refreshed for co-op.\n\nSandTogether is the community’s answer to a single-player game. Install it carefully, share your factory kindly, and pin a working mod version before the next official patch.