Devise: Disable password confirmation during sign-up

To disable password confirmation you can simply remove the password_confirmation field from the registration form. This disables the need to confirm the password entirely!

1. Generate devise views if you haven’t: rails g devise:views
2. Remove the password_confirmation section in app\views\devise\registrations\new.html.erb

The reason why this works lies in lib/devise/models/validatable.rb in the Devise source:

module Devise
  module Models
    module Validatable
 

      def self.included(base)

        base.class_eval do
          #....SNIP...
          validates_confirmation_of :password, :if => :password_required?
        end
      end
      
      #...SNIP...
      
      def password_required?
        !persisted? || !password.nil? || !password_confirmation.nil?
      end
    end
  end
end

Note that the validation is only triggered if password_required? returns true, and password_required? will return false if the password_confirmation field is nil.

Because where the password_confirmation field is present in the form, it will always be included in the parameters hash , as an empty string if it is left blank, the validation is triggered. However, if you remove the input from the form, the password_confirmation in the params will be nil, and therefore the validation will not be triggered.