A session controller for Devise that allows ajax logins.

sessions_controller.rb

class SessionsController < Devise::SessionsController
  
  def create
    resource = warden.authenticate!(:scope => resource_name, :recall => :failure)
    return sign_in_and_redirect(resource_name, resource)
  end
  
  def sign_in_and_redirect(resource_or_scope, resource=nil)
    scope = Devise::Mapping.find_scope!(resource_or_scope)
    resource ||= resource_or_scope
    sign_in(scope, resource) unless warden.user(scope) == resource
    return render :json => {:success => true, :redirect => stored_location_for(scope) || after_sign_in_path_for(resource)}
  end

  def failure
    return render:json => {:success => false, :errors => ["Login failed."]}
  end
end

Does your failure method is working?

I'm trying to do the same thing here, but when credentials are wrong, the default devise response is being sent instead.

See heartcombo/devise#3142 (comment)