SMAPI Steam Deck: How to Install and Update Stardew Valley Mods on Steam Deck

SMAPI (Stardew Modding API) is the open-source mod loader that powers nearly every major Stardew Valley mod. Without it, mods like Stardew Valley Expanded, NPC Adventures, and CJB Cheats Menu simply do not function. The Steam Deck runs SteamOS (Arch Linux-based), which means the install process differs from Windows — but it is entirely achievable in under 20 minutes using Desktop Mode. The SMAPI installer provides a Linux-compatible build, and Valve's open platform means no jailbreak or developer mode required beyond what is available by default. Once set up, your full mod list loads whether you are playing docked or in handheld mode, and Stardew Valley Expanded runs at a stable 60 FPS on the Steam Deck's hardware.

Step 1 — Switch to Desktop Mode: Hold the Power button, select 'Switch to Desktop.' The Steam Deck will load a KDE Plasma desktop environment. All subsequent steps happen here.

Step 2 — Download SMAPI: Open the Firefox browser in Desktop Mode and go to smapi.io. Download the latest SMAPI Linux installer (a `.zip` file). Save it to your Downloads folder.

Step 3 — Extract and Run the Installer: Open the Dolphin file manager, navigate to Downloads, right-click the SMAPI zip, and extract it. Open a terminal (Konsole), `cd` into the extracted folder, and run `bash install on Linux.sh`. The installer will detect your Stardew Valley installation path automatically if it is in the default Steam library location.

Step 4 — Select the Install Option: The installer presents numbered options. Choose '1' to install SMAPI. It will copy the necessary files and update your Steam launch options automatically.

Step 5 — Install Mods: Download mods from Nexus Mods as zip files. Extract each mod folder into: `~/.local/share/Steam/steamapps/common/Stardew Valley/Mods/`. Each mod should sit in its own subfolder containing the mod's `manifest.json`.

Step 6 — Return to Gaming Mode: Click 'Return to Gaming Mode' on the desktop. Launch Stardew Valley from Steam — SMAPI will load automatically before the game, listing all detected mods in its console overlay.

Stardew Valley Expanded: SVE is the largest content expansion mod for Stardew Valley, adding 50+ new locations, 27 new NPCs, and hundreds of hours of additional content. Install it the same way — extract to the Mods folder. SVE also requires the Content Patcher and SMAPI dependencies, which are listed on its Nexus Mods page.

Updating SMAPI on Steam Deck follows the same process as the initial install. When a new SMAPI version is released (typically after major Stardew Valley updates), download the latest installer from smapi.io, extract it, and run `bash install on Linux.sh` again. Select the install option — the updater overwrites the old SMAPI files while preserving your Mods folder and saves. After updating SMAPI, check each of your installed mods for compatibility with the new SMAPI version. Nexus Mods will show 'Compatible' status for mods that have been updated by their authors. Mods marked as broken post-update will display warnings in SMAPI's startup log.

Yes. Once SMAPI is installed, it integrates with Stardew Valley's Steam launch command. When you launch the game from Gaming Mode, SMAPI loads automatically in the background. You do not need to stay in Desktop Mode to play with mods.

SVE adds substantial content but Stardew Valley is not a demanding game. The Steam Deck handles SVE at 60 FPS with TDP set as low as 4–5W in most areas. New SVE locations with many active NPCs may dip to 55 FPS occasionally, but gameplay is smooth throughout. Set the Steam Deck refresh rate to 40 Hz for a stable experience that also extends battery life significantly.

Yes. Stardew Valley saves are stored at `%AppData%\StardewValley\Saves` on Windows and `~/.config/StardewValley/Saves` on Linux (Steam Deck). Copy the save folder from your PC and paste it into the same path on the Steam Deck via Desktop Mode. As long as the same mods are installed on both devices, your save will load without issues.