EU CAPTCHA for Ruby on Rails

Frequently Asked Questions

• How do I verify a CAPTCHA token in Ruby on Rails?

  Add the EU CAPTCHA Ruby gem to your Gemfile and run bundle install. Create a Rails initializer to configure the client with your secret key. In your controller action, read params[:eu_captcha_response], call the client's verify method, and redirect back with an error message if verification fails or proceed with the form data if it succeeds.

• Is there an official EU CAPTCHA Ruby gem?

  Yes. EU CAPTCHA provides an official Ruby client generated from the OpenAPI specification. Add it to your Gemfile and run bundle install. The gem supports Ruby 2.7 and later and provides an idiomatic Ruby interface for calling the EU CAPTCHA verification API.

• How do I add EU CAPTCHA to a Rails controller action?

  In your create or update action, read the eu-captcha-response token from the params hash. Call the EU CAPTCHA client's verify method with your secret key and the token. If verification fails, add an error to the model or flash and re-render the form. If it succeeds, proceed with saving the record or processing the submission.

• Can I use EU CAPTCHA with a Rails before_action callback?

  Yes. Define a private method in your controller that performs the EU CAPTCHA verification and add it as a before_action for the actions you want to protect. If verification fails, the before_action renders an error response and prevents the main action from running, keeping your controller actions clean and DRY.

• Does EU CAPTCHA work with Sinatra or other Ruby frameworks?

  Yes. The EU CAPTCHA Ruby client is framework-agnostic and works with Sinatra, Hanami, Grape, or any other Ruby web framework. In a Sinatra route, read the eu-captcha-response from the params hash, call the client's verify method, and halt with an error status if verification fails.

• How do I configure the EU CAPTCHA client in a Rails initializer?

  Create a file at config/initializers/eu_captcha.rb. Inside, configure the EU CAPTCHA client with your secret key, reading it from Rails credentials or an environment variable using ENV['EU_CAPTCHA_SECRET_KEY']. Never hardcode the secret key in source code that is committed to version control.

• Is EU CAPTCHA GDPR compliant for Ruby on Rails applications?

  Yes. EU CAPTCHA is operated by an EU-based company, is hosted entirely in Germany, and does not rely on US cloud providers or infrastructure subject to US surveillance laws. The service processes only the data necessary to provide and verify the CAPTCHA (such as IP address and technical browser information) in line with GDPR Article 28. Your organization remains responsible for providing transparent privacy information, selecting an appropriate legal basis, and obtaining any required consent for your specific implementation. This information does not constitute legal advice; please consult your legal counsel for an assessment of your individual case.