Firebase Password Validation allowed regex

Your understanding is correct - the only requirement is a minimum of 6 chars.

However, if you are building Android/iOS apps, I would suggest -not- to hardcode the validation logic in your app, since the new user signup request is handled by Firebase Auth server.

For anyone looking for a regular expression to validate password before sending to firebase.

I suggest to use this pattern as it pass as minimum qualifications! also firebase verify and validate password after you send it too Firebase cloud... so keep it simple.

let pattern: String = "(?=.*[0-9a-zA-Z]).{6,}"
  1. Minimum 6 character: {6,}
  2. Any character allowed: (?=.*[0-9a-zA-Z])

Remember, it is just the minimum requirements for a valid password, you can choose how strong the password should be based on your software.