Firebase - How to set security rules so that only logged in users can read and write?

Firebase - How to set security rules so that only logged in users can read and write for a specific table?

For the logins I'm using firebase built in authentication.

Solution

You can check on the auth variable

{
  "rules": {
    "posts": {
      "$post_id": {
        ".write": "auth != null"
      }
    }
  }
}