Slime Rancher Modding on OpenMods

A first-person ranch sim with a friendly modding community

Slime Rancher (2017) is a Unity game built on Mono, which puts it in the comfortable middle of the modding-difficulty spectrum: easy to inject into, well-documented by years of community work, and not so popular that load-bearing modders have moved on. Monomi Park never officially supported modding, but they've been tolerant of it, and the community settled on a stable stack early.

That stack is MelonLoader plus a small set of community frameworks. If you've modded any other Mono Unity game (Slay the Spire, Among Us pre-IL2CPP, BTD6), the patterns transfer directly.

The toolchain

• MelonLoader: the plugin loader, by Lava Gang. Drops alongside SlimeRancher.exe, intercepts the Mono runtime, and loads any .dll placed in Mods/.
• Slime Rancher Mod Loader (SRML): a Slime Rancher–specific layer on top of MelonLoader maintained by the community. Provides type-safe APIs for adding new slime types, resources, gadgets, and zones.

Mods are typically C# class libraries inheriting from SRMLMod (the SRML base class), built against the game's Assembly-CSharp.dll. They ship as a single .dll dropped into Mods/.

What you'll find on OpenMods

Most Slime Rancher mods historically live on Nexus Mods and the SRML community Discord. GitHub is where many modders keep their source. OpenMods catalogues the GitHub-published Slime Rancher mods, typically content additions (new slimes, new zones) or quality-of-life tools.

Practical notes

• Slime Rancher 1 and Slime Rancher 2 use entirely different stacks. SR1 is Mono Unity with MelonLoader and SRML. SR2 is IL2CPP Unity with a separate, less mature mod ecosystem. Mods don't transfer between them.
• Save compatibility is mod-specific. Pure-script mods can usually be removed safely. Mods that add new slime types or save-persisted items will leave dangling references in saves, back up first.
• The game runs against an old Unity version. Slime Rancher 1 hasn't had a major Unity engine upgrade in years, which is actually good for modders: the modding API is stable.
• Monomi Park's tolerant stance isn't a guarantee. Always read each mod's licence, most are MIT or CC-BY-NC. Don't redistribute paid content modifications.