How to use an API Key for your Factorio Server
In order for your Factorio server to show up on the browser lists for players to join, you need to provide user credentials. It can be your factorio.com Username and Password, or Authentication Token, also know as an API Key or Service Token. This article will show you where you can find your API Key so you can add it to your Factorio Dedicated Server.
Make a Factorio Account
If you haven't done so already, you'll want to make an account at https://factorio.com/ . The login credentials from the Factorio website are an option to allow your server to show on the browser listings. If you've purchased your copy from Steam, you can link your Factorio account with your Steam account.
Where to Find Your API Key
You can also find your Authentication Token within your games files. It will be in a file called player-data.json. The default Steam location for this file on Windows is in: %appdata%\Factorio
Inside the player-data.json file, look for the line that says service-token. This string of numbers and letters is your API Key/Authentication Token.
Add the Key to Your Factorio Server
Now let's add the API Key to your Factorio server.
On your Game Control Panel, navigate to the "Startup" page on the top, then to the "Auth Token" box. You can provide either your Factorio login credentials in the Username and Password text fields OR your API Token. It has to be one or the other.
You're now all set to turn your server on, and it will show up in the in-game server listings.
