Devise disable signup

routes

devise_for :users, :skip => [:registrations] 
as :user do
  get 'users/edit' => 'devise/registrations#edit', :as => 'edit_user_registration'
  put 'users' => 'devise/registrations#update', :as => 'user_registration'
end

# And then modify the app/views/devise/shared/_links.erb

Another way to do it is to remove :registerable from your Devise model and all of this other stuff should happen automatically.

If you remove registerable from the User model (in this case), then you wont be able to edit a user object. You won't be able to perform: edit_user_registration_path
The idea is to prevent from creating new users, not to also prevent from editing the already existing users.

I guess it depends on what you're editing about them. Removing registerable still allows existing users to change their passwords and some other basic stuff, just not any stuff you have in registration like their email address or cancelling an account.

I agree with @CoryFoy, removing :registerable from the model makes the sign up link not to be rendered in the form and the route not being generated.