public sealed struct Sandbox.SteamId

If you are using HTTP requests or WebSockets in your game, you can use Auth Tokens to validate that the requests were sent from a valid Steam user in a s&box game session. This is useful if you want to tie data to a specific Steam account, or prevent botting.

Components can contain RPCs. An RPC is a function that when called, is called remotely too.

On a Dedicated Server, you can specify who is an admin of your server, or customize permissions even further with claims for individual Steam accounts.

The API for leaderboards is publically accessible. Have fun!

Errors will happen. Here's how to make a useful error report.