diff --git a/app/controllers/better_together/users/registrations_controller.rb b/app/controllers/better_together/users/registrations_controller.rb
index e5dedc419..256c727b7 100644
--- a/app/controllers/better_together/users/registrations_controller.rb
+++ b/app/controllers/better_together/users/registrations_controller.rb
@@ -74,12 +74,19 @@ def new
         end
       end
 
-      def create
+      def create # rubocop:todo Metrics/MethodLength
         unless agreements_accepted?
           handle_agreements_not_accepted
           return
         end
 
+        # Validate captcha if enabled by host application
+        unless validate_captcha_if_enabled?
+          build_resource(sign_up_params)
+          handle_captcha_validation_failure(resource)
+          return
+        end
+
         ActiveRecord::Base.transaction do
           super do |user|
             handle_user_creation(user) if user.persisted?
@@ -104,6 +111,25 @@ def set_required_agreements
         @code_of_conduct_agreement = BetterTogether::Agreement.find_by(identifier: 'code_of_conduct')
       end
 
+      # Hook method for host applications to implement captcha validation
+      # Override this method in host applications to add Turnstile or other captcha validation
+      # @return [Boolean] true if captcha is valid or not enabled, false if validation fails
+      def validate_captcha_if_enabled?
+        # Default implementation - no captcha validation
+        # Host applications should override this method to implement their captcha logic
+        true
+      end
+
+      # Hook method for host applications to handle captcha validation failures
+      # Override this method in host applications to customize error handling
+      # @param resource [User] the user resource being created
+      def handle_captcha_validation_failure(resource)
+        # Default implementation - adds a generic error message
+        resource.errors.add(:base, I18n.t('better_together.registrations.captcha_validation_failed',
+                                          default: 'Security verification failed. Please try again.'))
+        respond_with resource
+      end
+
       def after_sign_up_path_for(resource)
         # Redirect to event if signed up via event invitation
         return better_together.event_path(@event_invitation.event) if @event_invitation&.event
diff --git a/app/views/devise/registrations/_extra_registration_fields.html.erb b/app/views/devise/registrations/_extra_registration_fields.html.erb
new file mode 100644
index 000000000..11bb237e9
--- /dev/null
+++ b/app/views/devise/registrations/_extra_registration_fields.html.erb
@@ -0,0 +1,3 @@
+<%# Override this partial in your host app to add additional fields to the registration form %>
+<%# Place custom form elements here (e.g., CAPTCHA, extra validation fields, etc.) %>
+<%# Available locals: form (form builder), resource (user resource being created) %>
diff --git a/app/views/devise/registrations/new.html.erb b/app/views/devise/registrations/new.html.erb
index 432aa3e1d..4206b1e52 100644
--- a/app/views/devise/registrations/new.html.erb
+++ b/app/views/devise/registrations/new.html.erb
@@ -29,112 +29,119 @@
   <% else %>
     <div class="row justify-content-center">
       <div class="col-md-6">
-        <h2 class="mb-4"><%= t('.sign_up') %></h2>
+        <h2 id="registration-title" class="mb-4"><%= t('.sign_up') %></h2>
 
-        <%= form_for(resource, as: resource_name, url: registration_path(resource_name), html: { class: 'card card-body needs-validation', novalidate: true }, data: { controller: 'better_together--form-validation', turbo: false }) do |f| %>
+        <%= form_for(resource, as: resource_name, url: registration_path(resource_name), html: { id: 'registration-form', class: 'card card-body needs-validation registration-form', novalidate: true }, data: { controller: 'better_together--form-validation', turbo: false }) do |f| %>
           <%= render "devise/shared/error_messages", resource: resource %>
 
           <% if @platform_invitation %>
-            <%= hidden_field_tag :invitation_code, @platform_invitation.token %>
+            <%= hidden_field_tag :invitation_code, @platform_invitation.token, id: 'invitation-code-field' %>
           <% end %>
 
           <!-- Email Field -->
-          <div class="mb-3">
-            <%= f.label :email, t('.email.label'), class: 'form-label' %>
-            <%= f.email_field :email, autofocus: true, autocomplete: "email", class: 'form-control', required: true %>
-            <small class="form-text text-muted"><%= t('.email.help') %></small>
+          <div id="email-field-group" class="mb-3 form-field-group">
+            <%= f.label :email, t('.email.label'), class: 'form-label', for: 'user_email' %>
+            <%= f.email_field :email, autofocus: true, autocomplete: "email", class: 'form-control', required: true, id: 'user_email' %>
+            <small id="email-help-text" class="form-text text-muted"><%= t('.email.help') %></small>
           </div>
 
           <!-- Password Field -->
-          <div class="mb-3" data-controller="better_together--password-toggle">
-            <%= f.label :password, t('.password.label'), class: 'form-label' %>
+          <div id="password-field-group" class="mb-3 form-field-group" data-controller="better_together--password-toggle">
+            <%= f.label :password, t('.password.label'), class: 'form-label', for: 'user_password' %>
             <% if @minimum_password_length %>
-              <em><%= t('devise.shared.minimum_password_length', count: @minimum_password_length) %></em>
+              <em id="password-length-requirement"><%= t('devise.shared.minimum_password_length', count: @minimum_password_length) %></em>
             <% end %>
             <div class="input-group">
-              <%= f.password_field :password, autocomplete: "current-password", class: 'form-control', "data-target": "better_together--password-toggle.field", required: true, minlength: @minimum_password_length || 12 %>
-              <button type="button" data-action="click->better_together--password-toggle#password" class="btn btn-outline-secondary" data-bs-toggle="tooltip" title="<%= t('devise.sessions.new.password.toggle') %>">
+              <%= f.password_field :password, autocomplete: "current-password", class: 'form-control', "data-target": "better_together--password-toggle.field", required: true, minlength: @minimum_password_length || 12, id: 'user_password' %>
+              <button id="password-toggle-btn" type="button" data-action="click->better_together--password-toggle#password" class="btn btn-outline-secondary" data-bs-toggle="tooltip" title="<%= t('devise.sessions.new.password.toggle') %>">
                 <i class="password-field-icon-1 far fa-eye-slash" data-target="better_together--password-toggle.icon"></i>
               </button>
             </div>
-            <small class="form-text text-muted"><%= t('.password.help') %></small>
+            <small id="password-help-text" class="form-text text-muted"><%= t('.password.help') %></small>
           </div>
 
           <!-- Password Confirmation Field -->
-          <div class="mb-3" data-controller="better_together--password-toggle">
-            <%= f.label :password_confirmation, t('.password_confirmation.label'), class: 'form-label' %>
+          <div id="password-confirmation-field-group" class="mb-3 form-field-group" data-controller="better_together--password-toggle">
+            <%= f.label :password_confirmation, t('.password_confirmation.label'), class: 'form-label', for: 'user_password_confirmation' %>
 
             <div class="input-group">
-              <%= f.password_field :password_confirmation, autocomplete: "current-password", class: 'form-control', "data-target": "better_together--password-toggle.field", required: true, minlength: @minimum_password_length || 12 %>
-              <button type="button" data-action="click->better_together--password-toggle#password" class="btn btn-outline-secondary" data-bs-toggle="tooltip" title="<%= t('devise.sessions.new.password.toggle') %>">
+              <%= f.password_field :password_confirmation, autocomplete: "current-password", class: 'form-control', "data-target": "better_together--password-toggle.field", required: true, minlength: @minimum_password_length || 12, id: 'user_password_confirmation' %>
+              <button id="password-confirmation-toggle-btn" type="button" data-action="click->better_together--password-toggle#password" class="btn btn-outline-secondary" data-bs-toggle="tooltip" title="<%= t('devise.sessions.new.password.toggle') %>">
                 <i class="password-field-icon-1 far fa-eye-slash" data-target="better_together--password-toggle.icon"></i>
               </button>
             </div>
-            <small class="form-text text-muted"><%= t('.password_confirmation.help') %></small>
+            <small id="password-confirmation-help-text" class="form-text text-muted"><%= t('.password_confirmation.help') %></small>
           </div>
 
-          <div id="profile-details" class="mb-4">
-            <h4><%= t('.profile_details') %></h4>
+          <div id="profile-details" class="mb-4 profile-details-section">
+            <h4 id="profile-details-title"><%= t('.profile_details') %></h4>
             <!-- Person Identification Fields -->
             <%= f.fields_for :person do |person_form| %>
               <!-- Name Field -->
-              <div class="mb-3">
-                <%= person_form.label :name, t('.person.name'), class: 'form-label' %>
-                <%= person_form.text_field :name, class: "form-control", required: true %>
-                <small class="form-text text-muted"><%= t('.person.name_hint') %></small>
+              <div id="name-field-group" class="mb-3 form-field-group">
+                <%= person_form.label :name, t('.person.name'), class: 'form-label', for: 'user_person_attributes_name' %>
+                <%= person_form.text_field :name, class: "form-control", required: true, id: 'user_person_attributes_name' %>
+                <small id="name-help-text" class="form-text text-muted"><%= t('.person.name_hint') %></small>
               </div>
 
               <!-- Username Field -->
-              <div class="mb-3">
-                <%= person_form.label :identifier, t('.person.identifier'), class: 'form-label' %>
-                <%= person_form.text_field :identifier, class: "form-control", required: true, minlength: 3 %>
+              <div id="identifier-field-group" class="mb-3 form-field-group">
+                <%= person_form.label :identifier, t('.person.identifier'), class: 'form-label', for: 'user_person_attributes_identifier' %>
+                <%= person_form.text_field :identifier, class: "form-control", required: true, minlength: 3, id: 'user_person_attributes_identifier' %>
                 <!-- Hint text for the Handle -->
-                <small class="form-text text-muted"><%= t('.person.identifier_hint_html', platform: host_platform) %></small>
+                <small id="identifier-help-text" class="form-text text-muted"><%= t('.person.identifier_hint_html', platform: host_platform) %></small>
               </div>
 
               <!-- Description Field -->
-              <div class="mb-3">
-                <%= person_form.label :description, t('.person.description'), class: 'form-label' %>
-                <%= person_form.text_area :description, class: "form-control" %>
-                <small class="form-text text-muted"><%= t('.person.description_hint') %></small>
+              <div id="description-field-group" class="mb-3 form-field-group">
+                <%= person_form.label :description, t('.person.description'), class: 'form-label', for: 'user_person_attributes_description' %>
+                <%= person_form.text_area :description, class: "form-control", id: 'user_person_attributes_description' %>
+                <small id="description-help-text" class="form-text text-muted"><%= t('.person.description_hint') %></small>
           </div>
         <% end %>
       </div>
 
       <% if @terms_of_service_agreement || @privacy_policy_agreement || @code_of_conduct_agreement %>
+        <div id="agreements-section" class="agreements-section">
         <% if @terms_of_service_agreement %>
-          <div class="mb-3 form-check">
-            <%= check_box_tag :terms_of_service_agreement, '1', false, class: 'form-check-input agreement-checkbox', data: { agreement_identifier: 'terms_of_service' }, required: true, aria: { describedby: 'terms-of-service-summary', disabled: 'true' } %>
-            <%= label_tag :terms_of_service_agreement, t('.terms_of_service.label'), class: 'form-check-label' %>
+          <div id="terms-of-service-agreement-group" class="mb-3 form-check agreement-group">
+            <%= check_box_tag :terms_of_service_agreement, '1', false, class: 'form-check-input agreement-checkbox', data: { agreement_identifier: 'terms_of_service' }, required: true, aria: { describedby: 'terms-of-service-summary', disabled: 'true' }, id: 'terms_of_service_agreement_checkbox' %>
+            <%= label_tag :terms_of_service_agreement, t('.terms_of_service.label'), class: 'form-check-label', for: 'terms_of_service_agreement_checkbox' %>
             <%= link_to t('.view', default: 'View'), agreement_path(@terms_of_service_agreement, locale: I18n.locale), class: 'ms-2 agreement-modal-link', role: 'button', data: { agreement_identifier: 'terms_of_service' } %>
-            <p id="terms-of-service-summary" class="form-text text-muted"><%= @terms_of_service_agreement.description %></p>
+            <small id="terms-of-service-summary" class="form-text text-muted"><%= @terms_of_service_agreement.description %></small>
           </div>
         <% end %>
 
         <% if @privacy_policy_agreement %>
-          <div class="mb-3 form-check">
-            <%= check_box_tag :privacy_policy_agreement, '1', false, class: 'form-check-input agreement-checkbox', data: { agreement_identifier: 'privacy_policy' }, required: true, aria: { describedby: 'privacy-policy-summary', disabled: 'true' } %>
-            <%= label_tag :privacy_policy_agreement, t('.privacy_policy.label'), class: 'form-check-label' %>
+          <div id="privacy-policy-agreement-group" class="mb-3 form-check agreement-group">
+            <%= check_box_tag :privacy_policy_agreement, '1', false, class: 'form-check-input agreement-checkbox', data: { agreement_identifier: 'privacy_policy' }, required: true, aria: { describedby: 'privacy-policy-summary', disabled: 'true' }, id: 'privacy_policy_agreement_checkbox' %>
+            <%= label_tag :privacy_policy_agreement, t('.privacy_policy.label'), class: 'form-check-label', for: 'privacy_policy_agreement_checkbox' %>
             <%= link_to t('.view', default: 'View'), agreement_path(@privacy_policy_agreement, locale: I18n.locale), class: 'ms-2 agreement-modal-link', role: 'button', data: { agreement_identifier: 'privacy_policy' } %>
-            <p id="privacy-policy-summary" class="form-text text-muted"><%= @privacy_policy_agreement.description %></p>
+            <small id="privacy-policy-summary" class="form-text text-muted"><%= @privacy_policy_agreement.description %></small>
           </div>
         <% end %>
 
         <% if @code_of_conduct_agreement %>
-          <div class="mb-3 form-check">
-            <%= check_box_tag :code_of_conduct_agreement, '1', false, class: 'form-check-input agreement-checkbox', data: { agreement_identifier: 'code_of_conduct' }, required: true, aria: { describedby: 'code-of-conduct-summary', disabled: 'true' } %>
-            <%= label_tag :code_of_conduct_agreement, t('.code_of_conduct.label'), class: 'form-check-label' %>
+          <div id="code-of-conduct-agreement-group" class="mb-3 form-check agreement-group">
+            <%= check_box_tag :code_of_conduct_agreement, '1', false, class: 'form-check-input agreement-checkbox', data: { agreement_identifier: 'code_of_conduct' }, required: true, aria: { describedby: 'code-of-conduct-summary', disabled: 'true' }, id: 'code_of_conduct_agreement_checkbox' %>
+            <%= label_tag :code_of_conduct_agreement, t('.code_of_conduct.label'), class: 'form-check-label', for: 'code_of_conduct_agreement_checkbox' %>
             <%= link_to t('.view', default: 'View'), agreement_path(@code_of_conduct_agreement, locale: I18n.locale), class: 'ms-2 agreement-modal-link', role: 'button', data: { agreement_identifier: 'code_of_conduct' } %>
-            <p id="code-of-conduct-summary" class="form-text text-muted"><%= @code_of_conduct_agreement.description %></p>
+            <small id="code-of-conduct-summary" class="form-text text-muted"><%= @code_of_conduct_agreement.description %></small>
           </div>
         <% end %>
+        </div>
       <% end %>
 
+      <!-- Host App Extensible Content (e.g., CAPTCHA, additional fields) -->
+      <%= render partial: 'devise/registrations/extra_registration_fields', locals: { form: f, resource: resource } %>
+
       <!-- Submit Button -->
-      <div class="text-center">
-        <%= f.submit t('.sign_up'), class: 'btn btn-primary' %>
+      <div id="submit-section" class="text-center submit-section">
+        <%= f.submit t('.sign_up'), class: 'btn btn-primary', id: 'registration-submit-btn' %>
             <!-- Additional Links -->
-            <%= render "devise/shared/links" %>
+            <div id="additional-links" class="additional-links">
+              <%= render "devise/shared/links" %>
+            </div>
           </div>
         <% end %>
       </div>
diff --git a/config/locales/en.yml b/config/locales/en.yml
index 64effabb7..6a49a1955 100644
--- a/config/locales/en.yml
+++ b/config/locales/en.yml
@@ -1418,6 +1418,8 @@ en:
       updated_on_short: Updated
       view_post: View Post
     primary: Primary
+    registrations:
+      captcha_validation_failed: Security verification failed. Please try again.
     remove: Remove
     resource_permissions:
       index:
@@ -1721,6 +1723,8 @@ en:
         agreements_must_accept: You must accept the Terms of Service and Privacy Policy
           to continue.
         agreements_required: You must accept the Privacy Policy and Terms of Service
+        captcha_validation_failed: Security verification failed. Please complete the
+          security check and try again.
         code_of_conduct:
           label: I agree to the Code of Conduct
         email:
diff --git a/config/locales/es.yml b/config/locales/es.yml
index 671f420b3..31edccb05 100644
--- a/config/locales/es.yml
+++ b/config/locales/es.yml
@@ -1428,6 +1428,9 @@ es:
       updated_on_short: Actualizado
       view_post: Ver publicación
     primary: Primario
+    registrations:
+      captcha_validation_failed: La verificación de seguridad falló. Por favor, inténtelo
+        de nuevo.
     remove: Eliminar
     resource_permissions:
       index:
@@ -1732,13 +1735,16 @@ es:
           actual para confirmar los cambios
       new:
         agreements:
-          privacy_policy: I agree to the Privacy Policy
-          terms_of_service: I agree to the Terms of Service
-        agreements_must_accept: You must accept the Terms of Service and Privacy Policy
-          to continue.
-        agreements_required: You must accept the Privacy Policy and Terms of Service
+          privacy_policy: Acepto la Política de Privacidad
+          terms_of_service: Acepto los Términos de Servicio
+        agreements_must_accept: Debe aceptar los Términos de Servicio y la Política
+          de Privacidad para continuar.
+        agreements_required: Debe aceptar la Política de Privacidad y los Términos
+          de Servicio
+        captcha_validation_failed: La verificación de seguridad falló. Por favor,
+          completa la verificación de seguridad e inténtalo de nuevo.
         code_of_conduct:
-          label: I agree to the Code of Conduct
+          label: Acepto el Código de Conducta
         email:
           help: Por favor, introduzca una dirección de correo válida.
           label: Correo Electrónico
@@ -1764,13 +1770,13 @@ es:
           name: Nombre
           name_hint: Por favor, proporcione su nombre completo.
         privacy_policy:
-          label: I agree to the Privacy Policy
+          label: Acepto la Política de Privacidad
         profile_details: Detalles del Perfil
         sign_up: Registrarse
         submit: Enviar
         terms_of_service:
-          label: I agree to the Terms of Service
-        view: View
+          label: Acepto los Términos de Servicio
+        view: Ver
       signed_up: Bienvenido. Tu cuenta fue creada.
       signed_up_but_inactive: Tu cuenta ha sido creada correctamente. Sin embargo,
         no hemos podido iniciar la sesión porque tu cuenta aún no está activada.
diff --git a/config/locales/fr.yml b/config/locales/fr.yml
index 5a0705485..60a48b25e 100644
--- a/config/locales/fr.yml
+++ b/config/locales/fr.yml
@@ -1435,6 +1435,8 @@ fr:
       updated_on_short: Mis à jour
       view_post: Voir la publication
     primary: Principal
+    registrations:
+      captcha_validation_failed: La vérification de sécurité a échoué. Veuillez réessayer.
     remove: Supprimer
     resource_permissions:
       index:
@@ -1740,13 +1742,16 @@ fr:
           votre mot de passe actuel pour valider ces modifications
       new:
         agreements:
-          privacy_policy: I agree to the Privacy Policy
-          terms_of_service: I agree to the Terms of Service
-        agreements_must_accept: You must accept the Terms of Service and Privacy Policy
-          to continue.
-        agreements_required: You must accept the Privacy Policy and Terms of Service
+          privacy_policy: J'accepte la Politique de Confidentialité
+          terms_of_service: J'accepte les Conditions d'Utilisation
+        agreements_must_accept: Vous devez accepter les Conditions d'Utilisation et
+          la Politique de Confidentialité pour continuer.
+        agreements_required: Vous devez accepter la Politique de Confidentialité et
+          les Conditions d'Utilisation
+        captcha_validation_failed: La vérification de sécurité a échoué. Veuillez
+          compléter la vérification de sécurité et réessayer.
         code_of_conduct:
-          label: I agree to the Code of Conduct
+          label: J'accepte le Code de Conduite
         email:
           help: Veuillez entrer une adresse email valide.
           label: Email
@@ -1772,13 +1777,13 @@ fr:
           name: Nom
           name_hint: Veuillez fournir votre nom complet.
         privacy_policy:
-          label: I agree to the Privacy Policy
+          label: J'accepte la Politique de Confidentialité
         profile_details: Détails du Profil
         sign_up: Inscription
         submit: Soumettre
         terms_of_service:
-          label: I agree to the Terms of Service
-        view: View
+          label: J'accepte les Conditions d'Utilisation
+        view: Voir
       signed_up: Bienvenue ! Vous vous êtes bien enregistré(e).
       signed_up_but_inactive: Vous vous êtes bien enregistré(e). Cependant, nous n’avons
         pas pu vous connecter car votre compte n’a pas encore été activé.
diff --git a/spec/controllers/better_together/users/registrations_controller_hook_spec.rb b/spec/controllers/better_together/users/registrations_controller_hook_spec.rb
new file mode 100644
index 000000000..e62d8039d
--- /dev/null
+++ b/spec/controllers/better_together/users/registrations_controller_hook_spec.rb
@@ -0,0 +1,41 @@
+# frozen_string_literal: true
+
+require 'rails_helper'
+
+RSpec.describe BetterTogether::Users::RegistrationsController, :skip_host_setup do
+  include BetterTogether::CapybaraFeatureHelpers
+
+  routes { BetterTogether::Engine.routes }
+
+  before do
+    configure_host_platform
+  end
+
+  describe 'captcha hook methods', :no_auth do
+    describe '#validate_captcha_if_enabled?' do
+      let(:controller_instance) { described_class.new }
+
+      it 'returns true by default (no captcha validation)' do
+        expect(controller_instance.send(:validate_captcha_if_enabled?)).to be true
+      end
+    end
+
+    describe '#handle_captcha_validation_failure' do
+      let(:user) { build(:better_together_user) }
+      let(:controller_instance) { described_class.new }
+
+      before do
+        allow(controller_instance).to receive(:respond_with)
+      end
+
+      it 'adds error to resource and calls respond_with' do
+        controller_instance.send(:handle_captcha_validation_failure, user)
+
+        expect(user.errors[:base]).to include('Security verification failed. Please try again.')
+        expect(controller_instance).to have_received(:respond_with).with(user)
+      end
+    end
+  end
+
+  # Integration test for the complete captcha flow will be handled in feature specs
+end