This page tells you how to download and install mods, and gives a quick overview of what you should keep in mind when creating a mod. For more detailed instructions on creating mods, you may view the modding tutorial page. If you are looking for the modding API, check out the official Factorio Lua API documentation website. If you wish to know where to install a mod which is in a zipped format, please read the instructions on the application directory page.
Downloading & installing mods
You can download the mods from the following places:
Mod portal (website)
Factorio's developers created the mod portal (website) to allow the players to share mods. A mod you download from the website comes in the form of a zipped file. To install the mod, you need to copy the zipped file into the mods directory located under the user data directory without unzipping it. You can verify whether or not you installed it correctly by viewing the mods list which you can access through the game's main menu.
Mod portal (in-game)
The mods displayed on the mod portal (website) should show in the in-game mod portal which you can access through the game's main menu. The differences in the in-game mod portal are that you can use it to both automatically download and install mods, and to enable or disable the mods.
Some mod creators upload their mods to the official mod subforum to showcase their work without submitting to the mod portal or to get feedbacks from the community on their mods before updating or sending them to the mod portal. An uploaded mod should show as an attachment. Occasionally, a mod you download from the subforum comes in the form of a zipped file. You need to copy it into the mods directory located under the user data directory to install it — you do not have to unzip it. You can verify whether or not you installed it correctly by viewing the mods list which you can access through the game's main menu.
Many mods use Factorio's base mod as their only dependency which you do not have to install separately. However, some mods may require you to install other mods for them to work and can also make suggestions for you to install other mods for them to extend their functionality.
When a mod you installed requires you to install another mod for it to work, the other mod, in this case, is a required dependency.
When a mod makes a suggestion to install another mod, but if it does not need that other mod for it to work, the other mod, in this case, is an optional dependency. You can install the optional dependencies which extend the functionality of a mod to enhance your gaming experience with the mod.
Currently, the in-game mod portal does not automatically download neither required nor optional dependencies; therefore, it is up to the user to find and install them. However, such process is expected to be made automatic in the future.
Factorio modding API
Factorio's modding API allows you to add new game entities and introduce new behaviors to the game — it offers many hooks which you can use to trigger new and exciting actions.
You need to use the Lua programming language to create any mods in Factorio. The game's mod system injects your code into the startup and to the data construction stage of the game. You can use any text editor to write the code for your mod. Well-known text editors that offer syntax highlighting for Lua are Notepad++ and Sublime Text.
Useful resources for Lua:
Basic structure of a mod
Factorio's mods are distributed in ZIP archives and contain several important files that Factorio looks for when loading mods. These files are listed below, and the required files are colored red.
Every mod requires a license since Factorio v0.11. If a mod has no license, it is assumed to have a Creative Commons license — Attribution-Noncommercial 4.0 International (CC BY-NC 4.0). However, it is possible to purposely make the mod unlicensed, to allow the code within it to be available to the public domain. The most popular distribution licenses for Factorio mods are the MIT license and the GPLv3 license.
Other useful legal links include: