Getting Started with Factorio Modding

Factorio modding is the cleanest "install a mod" flow in any game on this list. There's an official mod portal, an in-game browser, and a deterministic Lua scripting layer. No third-party tools. No script extender. Just subscribe-equivalent flow and play.

This guide walks the standard install on current Factorio (including Space Age, the 2024 expansion).

Step 1 — Use the in-game mod browser

Launch Factorio → Mods menu. Click Install to open the in-game mod browser, which pulls from the official mod portal.

Search and install. Factorio downloads, validates dependencies, and adds the mod to your active list automatically.

You can also visit mods.factorio.com in a browser, download .zip files, and drop them into %AppData%/Factorio/mods/ manually. The in-game browser is preferred — handles dependencies and version compatibility.

Step 2 — Install your first mods

Three popular first picks:

Squeak Through — minor change, lets the player squeeze between adjacent solid tiles. Universal first install.
Bottleneck or Bottleneck Lite — visual indicator showing which machines are blocked vs running. Diagnostic tool.
Factory Planner — production-line planning calculator inside the game.

These are pure QoL mods. They don't change the recipe tree or game balance.

Step 3 — Configure mods

Each mod can declare per-setting configuration. From the Mods menu, click any installed mod to see its settings tab.

Per-save settings vs runtime settings:

Some settings (recipe changes, tech costs) are locked when a save is created.
Runtime settings (UI behaviour, hotkeys) can change anytime.

For your first session, defaults are usually fine.

Step 4 — Multiplayer

Factorio's multiplayer auto-syncs mods. When you join a server:

Factorio detects the host's mod set.
Compares against your local mods.
Auto-downloads any missing mods from the official portal.
Restarts and joins.

This works because the official portal is the canonical source — Factorio knows where to find every mod the server is running.

Caveat: mods not on the official portal (rare, but possible for prerelease or private mods) won't auto-sync.

Step 5 — Optional: install a major overhaul

When you've finished vanilla Factorio (or Space Age) and want a substantially different experience:

Space Exploration (SE) — adds space travel, planets, orbital mechanics. Massive scope expansion. Note: SE pre-dated Space Age expansion; check compatibility.
Krastorio 2 — overhauls tech tree with new game stages.
Bob's mods + Angel's mods — the classic combined overhaul, deep recipe complexity.
Pyanodons — extreme complexity overhaul. Hundreds of hours per playthrough.

Install through the in-game browser. Most overhauls have dependency mods; the browser resolves them.

Step 6 — Save handling

Adding mods to existing save: usually safe. Mods that add new content take effect.
Removing mods from existing save: dangerous. If the save references mod content (items, recipes, entities), the save is broken.
Changing per-save mod settings mid-save: locked. Restart a new save to change them.

Back up saves before installing experimental mods.

Common gotchas

Mod dependency missing. Rare with the in-game browser (which auto-resolves). Common with manual installs. Solution: install dependencies first, then dependent mods.
Save corrupted after mod removal. As noted above. Re-install the removed mod.
Mod compatibility with Space Age. Some pre-Space-Age mods need updates. Check the mod's portal page for compatibility tags.
Multiplayer sync timeout. Slow internet + large mod set = long sync time. Be patient; Factorio handles it cleanly.
In-game browser empty. Internet issue. Restart Factorio.

If you're authoring your own mod, Factorio's modding documentation is well-maintained at wiki.factorio.com. The Lua API is documented exhaustively.