The eight routes to a mod
Every mod takes one of these routes, from cheapest to hardest. Experienced modders, and Universal Modder's agents, pick the cheapest route that can deliver the idea. Counts are field notes in the knowledge base.
Guide · game modding
What a game modder does, and how AI changed it
Modders keep games alive long after launch. Here's the craft in one page: the eight kinds of mods, the tools, where mods go, and what changes when an AI agent does the typing.
| Route | What it means | Examples | Notes |
|---|---|---|---|
| Data mod | Edit the game's own data files: stats, tables, scripts, scenarios. | AoE2 civs, BG3 stats, Darkest Dungeon randomizer | 22 |
| Asset swap | Replace or add textures, models, sounds without new code. | BG3 outfits, Starfield animation | 5 |
| Mod-loader API | Write code against a community mod loader's API. | tModLoader, Fabric, BepInEx, UE4SS Lua | 19 |
| Managed patch | Patch compiled .NET/Java code at runtime (Harmony, Mixin). | Schedule I on MelonLoader | 3 |
| Native hook | Hook native C++ functions with a DLL, ASI or proxy. | Elden Ring via me3, Mewgenics ImGui panel | 13 |
| Reimplementation | Rebuild a game's rules or runtime, reading your own game files. | Bloons TD 6 inside Minecraft, OpenTDU | 3 |
| Decomp / recomp | Decompile a game to source and recompile it, usually retro games. | N64 and PS-era decomp projects | 0 |
| Passthrough (game in a game) | Run two unmodified games together and exchange state: a game inside a game. | Minecraft inside GTA V, Portalcraft | 7 |
A modder's toolbox
- Mod loaders: BepInEx and MelonLoader (Unity), UE4SS (Unreal), tModLoader (Terraria), SMAPI (Stardew Valley), Fabric/NeoForge/Forge (Minecraft), SKSE (Skyrim), REFramework (RE Engine), ScriptHookV (GTA V).
- Decompilers and debuggers: ILSpy and dnSpy (.NET), Cpp2IL (IL2CPP), Vineflower (Java), Ghidra and IDA (native), Cheat Engine, x64dbg, Frida.
- Asset tools: FModel and UAssetGUI (Unreal), Blender, AssetRipper (Unity), format-specific converters.
- Graphics: RenderDoc to see render passes, ReShade for post-processing and depth.
- Mod managers: Vortex and Mod Organizer 2 to install and order other people's mods (how they differ).
How AI agents changed modding
Until 2025 a new mod meant learning the game's loader, decompiling its code and making art by hand. Coding agents now do much of that legwork. Toolkits such as Universal Modder give them the modder's method: recon first, smallest working slice, verify in the real game, and write down what was learned. The human modder becomes director and tester. More on AI modders →
Modder etiquette
- Never ship the game's files or decompiled code. Ship your code, your assets, or a patch.
- Credit the loaders, libraries and references you used.
- Disclose AI use. Communities react badly to undisclosed “vibe-coded” releases.
- Don't cheat in multiplayer, don't bypass anti-cheat or DRM.
- Write down what you learned. The next modder will thank you.
Where mods are published
| Platform | Best for |
|---|---|
| Nexus Mods | Most PC games, especially Bethesda, Baldur's Gate 3, Cyberpunk |
| Steam Workshop | Games with official Workshop support |
| Thunderstore | Unity games with BepInEx: Lethal Company, Valheim, Risk of Rain 2 |
| mod.io | Cross-platform official mod support |
| CurseForge / Modrinth | Minecraft |
| GitHub releases | Tools, frameworks and source-available mods |
Frequently asked questions
What is a modder?
A modder is someone who modifies a video game: adding content, changing mechanics, fixing bugs, improving graphics or combining games. Mods range from a one-line config tweak to total conversions that become new games.
Is modding games legal?
Modding games you own for personal use is broadly accepted, and many publishers have official mod tools and policies. Problems start with redistributing game files, bypassing DRM, cheating online, or monetizing someone else's IP. Read the publisher's mod policy.
What skills does a game modder need?
It depends on the mod. Data and asset mods need file-format knowledge and art tools; code mods need C#, Java, Lua or C++ plus a decompiler; native hooks need reverse engineering. AI agents now cover much of the coding and format work, so the human skill shifts toward judgement: what to build, and whether it actually works.
Where do modders publish mods?
Nexus Mods, Steam Workshop, Thunderstore (Unity/BepInEx games), mod.io, CurseForge and Modrinth (Minecraft), and GitHub releases.
Can I get paid as a game modder?
Some modders earn through donations, Patreon, Nexus Mods' donation points or official creator programs. Paywalling mods built on someone else's game raises legal risk, so check the publisher's rules first.