> It really isn't trivial. Rate limiting is great, but not enough. Rate limiting alone isn't a solution. But it can be part of a solution that doesn't require

> It really isn't trivial. Rate limiting is great, but not enough. Rate limiting alone isn't a solution. But it can be part of a solution that doesn't require reCAPTCHA. > If you lock people out after a certain number of failed login attempts, you allow an adversary to DOS your users by constantly trying to log in as them. That isn't how the pattern works. On next successful login you basically inform the user that they need to confirm it's them with an email token. It works well. ReCAPTCHA doesn't.