RimWorld Modding on OpenMods

A colony sim that became a modding platform

RimWorld is one of those games where the base experience is good, but the modded experience is what people actually play. Ludeon Studios builds RimWorld around a stable, well-documented C# codebase, and Tynan Sylvester has been unusually accommodating to modders for over a decade. The result is a modding scene that's smaller than Skyrim's but considerably more intricate — full conversions, alternative tech trees, faction overhauls, and entire genre shifts (medieval, Warhammer 40k, Star Wars, post-apocalyptic) all sit alongside each other and mostly cooperate.

If you're new, here's what's worth knowing.

Two install paths: Steam Workshop or manual

RimWorld supports modding natively without a third-party loader. Subscribe through the Steam Workshop and mods download into Steam/steamapps/workshop/content/294100/; install manually and they go into RimWorld/Mods/. Both locations are read on startup and shown in the in-game mod menu.

This matters because RimWorld has no SMAPI-equivalent. The game itself is the framework. Mods compile against Assembly-CSharp.dll and use Harmony for runtime patching — and that's it. You don't need to install a third-party launcher to start modding.

What you do need is Harmony if you plan to install any C# mod that patches game methods. Most modders ship it as a hard dependency. Subscribe to or download Harmony first, place it at the top of your mod load order, and everything that depends on it will resolve correctly.

Load order is the thing that breaks playthroughs

RimWorld doesn't enforce a load order — mods load in the order shown in the mod list, and any mod can override any earlier mod's content. This is a feature (it's why total conversions work) and a footgun (it's why your colonists are suddenly invisible).

The community-accepted rules of thumb:

Harmony first. Always.
Core, then Royalty, then Ideology, then Biotech, then Anomaly. DLCs go in chronological release order. Newer DLCs patch older ones.
HugsLib next. It's a small utility library a lot of mods depend on for keybinding registration and update notes. Treat it like Harmony.
Framework mods, then content mods, then patches, then UI tweaks. A "framework" mod is something like Combat Extended, Vanilla Expanded Framework, or Royalty Tweaks — they introduce new systems other mods build on top of.
Rocketman last. It's an optimisation mod that has to load after everything it's optimising.

RimPy is the community's load-order tool — it reads the dependency declarations in each mod's About.xml and proposes an order that satisfies them all. If you're running more than 50 mods, install RimPy. If you're running more than 200, install RimPy and use the auto-sort.

What you'll find on OpenMods

RimWorld's modding ecosystem traditionally lives on the Steam Workshop and GitHub, with GitHub typically being where the source lives and the Workshop being where the packaged build is published. OpenMods is well-suited to the GitHub side of that equation — if you're a RimWorld modder who already publishes to GitHub, listing your mod on OpenMods gives you a versioned download endpoint and discoverability outside the Workshop walled garden.

Browse the catalogue below for currently published RimWorld mods.

A few practical notes

The dev mode (? icon → Options → Development mode) is unusually powerful. RimWorld ships with an in-game scenario editor, debug actions, and a god-mode toggle. You can use these to test mod compatibility without starting a new colony.
Saves embed the mod list. When you save a colony, RimWorld records which mods were active. Loading the save on a different mod set produces a warning — and often a broken colony. Keep "save profiles" of working mod combinations.
Big mods are big. Vanilla Expanded alone is 25+ separate modules; Combat Extended changes nearly every weapon and gear stat. Mixing two ambitious framework mods often produces incompatibilities — read the framework's compatibility notes before piling on.

RimWorld's modding scene rewards patience. The best storytelling colonies on Reddit and YouTube are almost always running 100+ mods that took the player a weekend to configure. If that's daunting, start with five or ten quality-of-life mods (Allow Tool, Smart Speed, Replace Stuff, Wall Light, Common Sense) and build from there.