ActionController::RoutingError

ActionController::RoutingError is raised when Rails cannot find a route matching the requested URL. This typically results in a 404 Not Found response.

Common causes

• User accessing non-existent URL
• Broken links within the application
• Missing route definition in routes.rb
• Incorrect HTTP method for route
• Bots/crawlers accessing invalid paths

How to fix it

• Add catch-all route for custom 404 page
• Verify route exists with rails routes
• Check for typos in link_to paths
• Use named route helpers instead of hardcoded paths
• Implement proper 404 monitoring to find broken links

Example

# Error when accessing /nonexistent
# => ActionController::RoutingError: No route matches [GET] "/nonexistent"

# Add catch-all route (at end of routes.rb)
Rails.application.routes.draw do
  # ... other routes ...

  match '*path', to: 'errors#not_found', via: :all
end

# ErrorsController
class ErrorsController < ApplicationController
  def not_found
    render file: 'public/404.html', status: :not_found
  end
end

Related errors