How to test production rails exceptions while in development mode

Posted by win
on Friday, April 11

Recently found an easy way to test rails exceptions raised in production while in development.

Though you could just as easily use:

script/server -e production

Short of that the following works perfectly:

Update config/development.rb


config.action_controller.consider_all_requests_local = false


config.action_controller.consider_all_requests_local = true

Then update controllers/application.rb

add as the last method (unless you have additional protected methods then add to those):

  def local_request?

This works because rails will check if a raised exception is a local request. If it is a local request the “development” mode error screen will be presented to you like this:

Otherwise the 500 or 404 error pages will be displayed to the user.

Both modifications are needed since there are two ways a request is considered local 1.) which is controlled in the config folder and 2.) A request is also considered local if the request is being served on the local machine (


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