diff --git a/web/modules/custom/sdc_validator/drush.services.yml b/web/modules/custom/sdc_validator/drush.services.yml
new file mode 100644
index 000000000..01affa37e
--- /dev/null
+++ b/web/modules/custom/sdc_validator/drush.services.yml
@@ -0,0 +1,6 @@
+services:
+  sdc_validator.commands:
+    class: \Drupal\sdc_validator\Commands\ValidateComponentCommand
+    arguments: ['@plugin.manager.sdc', '@twig']
+    tags:
+      - { name: drush.command }
diff --git a/web/modules/custom/sdc_validator/phpunit.xml.dist b/web/modules/custom/sdc_validator/phpunit.xml.dist
new file mode 100644
index 000000000..b373d6f4b
--- /dev/null
+++ b/web/modules/custom/sdc_validator/phpunit.xml.dist
@@ -0,0 +1,25 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<phpunit xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:noNamespaceSchemaLocation="https://schema.phpunit.de/9.5/phpunit.xsd"
+         bootstrap="../build/web/core/tests/bootstrap.php"
+         colors="true"
+         cacheResultFile="../build/.phpunit.cache/test-results"
+         executionOrder="depends,defects"
+         beStrictAboutOutputDuringTests="true"
+         beStrictAboutTodoAnnotatedTests="true"
+         convertWarningsToExceptions="false"
+         failOnRisky="true"
+         failOnWarning="false"
+         verbose="true">
+    <testsuites>
+        <testsuite name="sdc_validator">
+            <directory>./tests/src/</directory>
+        </testsuite>
+    </testsuites>
+    <php>
+        <ini name="error_reporting" value="-1" />
+        <server name="KERNEL_DIR" value="../build/web/core" />
+        <env name="SIMPLETEST_BASE_URL" value="http://localhost" />
+        <env name="SIMPLETEST_DB" value="sqlite://localhost/sites/default/files/.ht.sqlite" />
+    </php>
+</phpunit>
diff --git a/web/modules/custom/sdc_validator/sdc_validator.info.yml b/web/modules/custom/sdc_validator/sdc_validator.info.yml
new file mode 100644
index 000000000..67dbcb484
--- /dev/null
+++ b/web/modules/custom/sdc_validator/sdc_validator.info.yml
@@ -0,0 +1,5 @@
+name: Single Directory Component Validator
+type: module
+description: 'Validator for Single Directory components.'
+package: Custom
+core_version_requirement: ^10 || ^11
diff --git a/web/modules/custom/sdc_validator/sdc_validator.module b/web/modules/custom/sdc_validator/sdc_validator.module
new file mode 100644
index 000000000..d55bd636b
--- /dev/null
+++ b/web/modules/custom/sdc_validator/sdc_validator.module
@@ -0,0 +1,37 @@
+<?php
+
+/**
+ * @file
+ */
+
+declare(strict_types=1);
+
+/**
+ * @file
+ * CivicTheme Development module.
+ */
+
+/**
+ * Implements hook_twig_validator_rule_info_alter().
+ */
+function sdc_validator_twig_validator_rule_info_alter(array &$info): void {
+  // @see https://www.drupal.org/project/sdc_devel/issues/3517321
+  $rule_name_ignore = -1;
+  $rule_name_error = 3;
+  $rule_name_warning = 4;
+  $rule_name_notice = 5;
+
+  $info['filter']['rule_on_name'][$rule_name_ignore][] = 'raw';
+
+  // Ignore "Use slots instead of hard embedding a component in the template with `@name`.".
+  unset($info['include']);
+  // Ignore "Use slots instead of hard embedding a component in the template with `includ\r\ne`.".
+  unset($info['function']['rule_on_name'][$rule_name_error]['parent']);
+  // Ignore "Replace with Twig function include()".
+  unset($info['function']['rule_on_name'][$rule_name_notice]['pattern']);
+  // Ignore "Careful with Twig function: `source`. Bad architecture, but sometimes needed\r\n for shared static files.".
+  $info['function']['rule_on_name'][$rule_name_ignore][] = 'source';
+  unset($info['function']['rule_on_name'][$rule_name_warning]['source']);
+  // Ignore "`is iterable` test is too ambiguous. Use `is sequence` or `is mapping`.".
+  unset($info['test']);
+}
diff --git a/web/modules/custom/sdc_validator/src/Commands/ValidateComponentCommand.php b/web/modules/custom/sdc_validator/src/Commands/ValidateComponentCommand.php
new file mode 100644
index 000000000..8e2e44b01
--- /dev/null
+++ b/web/modules/custom/sdc_validator/src/Commands/ValidateComponentCommand.php
@@ -0,0 +1,222 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Drupal\sdc_validator\Commands;
+
+use Consolidation\AnnotatedCommand\CommandResult;
+use Drupal\Core\Plugin\Component;
+use Drupal\Core\Render\Component\Exception\InvalidComponentException;
+use Drupal\Core\Template\ComponentNodeVisitor;
+use Drupal\Core\Template\TwigEnvironment;
+use Drupal\Core\Theme\Component\ComponentValidator;
+use Drupal\Core\Theme\ComponentPluginManager;
+use Drush\Commands\DrushCommands;
+use Psy\Command\Command;
+use Symfony\Component\Yaml\Yaml;
+use Twig\Error\Error;
+
+/**
+ * Validates SDC component definitions using Drupal core's ComponentValidator.
+ *
+ * @package Drupal\sdc_validator\Commands
+ */
+class ValidateComponentCommand extends DrushCommands {
+
+  /**
+   * Defines the component validator.
+   */
+  protected ComponentValidator $componentValidator;
+
+  /**
+   * Validates slots of a component.
+   */
+  protected ComponentNodeVisitor $componentSlotValidator;
+
+  /**
+   * {@inheritdoc}
+   */
+  public function __construct(protected ComponentPluginManager $componentPluginManager, protected TwigEnvironment $twig) {
+    parent::__construct();
+    $this->componentValidator = new ComponentValidator();
+    $this->componentValidator->setValidator();
+    $this->componentSlotValidator = new ComponentNodeVisitor($this->componentPluginManager);
+  }
+
+  /**
+   * Validates all component definitions in a given path.
+   *
+   * @param string $components_path
+   *   Path to the directory containing component folders.
+   *
+   * @command sdc_validator:validate
+   * @usage drush sdc_validator:validate '<path to components>'
+   * @usage drush sdc_validator:validate 'web/themes/custom/civictheme/components'
+   *
+   * @SuppressWarnings(PHPMD.StaticAccess)
+   */
+  public function validateComponentDefinitions(string $components_path): CommandResult {
+    if (!is_dir($components_path)) {
+      throw new \Exception('❌ Components directory not found: ' . $components_path);
+    }
+    $this->output()->writeln(sprintf('🔍 Validating components in %s', $components_path));
+    $component_path_parts = explode('/', $components_path);
+    array_filter($component_path_parts);
+    $component_base_identifier = $component_path_parts[count($component_path_parts) - 2] ?? NULL;
+    if ($component_base_identifier === NULL) {
+      throw new \Exception('❌ Cannot validate components that are not located in a theme or a module: ' . $components_path);
+    }
+    $component_files = [];
+    $iterator = new \RecursiveIteratorIterator(
+      new \RecursiveDirectoryIterator($components_path),
+      \RecursiveIteratorIterator::SELF_FIRST
+    );
+    foreach ($iterator as $file) {
+      if ($file->isFile() && $file->getExtension() === 'yml' && str_ends_with((string) $file->getFilename(), '.component.yml')) {
+        $component_files[] = $file->getPathname();
+      }
+    }
+
+    if (empty($component_files)) {
+      throw new \Exception('❌ No component definition files found in: ' . $components_path);
+    }
+
+    $errors = [];
+    $valid_count = 0;
+
+    foreach ($component_files as $component_file) {
+      try {
+        $component_name = basename((string) $component_file, '.component.yml');
+        $component_id = $component_base_identifier . ':' . $component_name;
+        $component = $this->componentPluginManager->find($component_id);
+        $this->validateSlots($component);
+        $this->validateComponentFile($component_file, $component_id);
+        $valid_count++;
+      }
+      catch (\Exception $e) {
+        $errors[] = [
+          'file' => basename((string) $component_file),
+          'error' => $e->getMessage(),
+        ];
+      }
+    }
+
+    // Display summary.
+    if ($valid_count > 0) {
+      $this->output()->writeln(sprintf("✅ %d components are valid", $valid_count));
+    }
+    if ($errors !== []) {
+      $this->output()->writeln("Failed components:");
+      foreach ($errors as $error) {
+        $this->output()->writeln(sprintf("❌ %s - %s", $error['file'], $error['error']));
+      }
+      return CommandResult::dataWithExitCode('Component validation failed.', Command::FAILURE);
+    }
+    return CommandResult::dataWithExitCode('✨ All components are valid', Command::SUCCESS);
+  }
+
+  /**
+   * Validates a single component definition file.
+   *
+   * @param string $component_file
+   *   Path to the file.
+   * @param string $component_id
+   *   The component id.
+   *
+   * @throws \Drupal\Core\Render\Component\Exception\InvalidComponentException
+   */
+  public function validateComponentFile(string $component_file, string $component_id): void {
+    [, $component_name] = explode(':', $component_id);
+    $definition = Yaml::parseFile($component_file);
+    // Merge with additional required keys.
+    $definition = array_merge(
+      $definition,
+      [
+        'machineName' => $component_name,
+        'extension_type' => 'theme',
+        'id' => $component_id,
+        'library' => ['css' => ['component' => ['foo.css' => []]]],
+        'path' => '',
+        'provider' => 'civictheme',
+        'template' => $component_name . '.twig',
+        'group' => 'civictheme-group',
+        'description' => 'CivicTheme component',
+      ]
+    );
+    $this->componentValidator->validateDefinition($definition, TRUE);
+  }
+
+  /**
+   * Moved from \Drupal\Core\Template\ComponentNodeVisitor::validateSlots.
+   *
+   * Performs a cheap validation of the slots in the template.
+   *
+   * It validates them against the JSON Schema provided in the component
+   * definition file and massaged in the ComponentMetadata class. We don't use
+   * the JSON Schema validator because we just want to validate required and
+   * undeclared slots. This cheap validation lets us validate during runtime
+   * even in production.
+   *
+   * @param \Drupal\Core\Plugin\Component $component
+   *   The component to validate the slots against.
+   *
+   * @throws \Drupal\Core\Render\Component\Exception\InvalidComponentException
+   *   When the twig doesn't parse or template does not exist.
+   * @throws \Exception
+   *   When the slots don't pass validation.
+   *
+   * @see \Drupal\Core\Template\ComponentNodeVisitor::validateSlots
+   */
+  protected function validateSlots(Component $component): void {
+    $template_path = $component->getTemplatePath();
+    if ($template_path === NULL) {
+      throw new \Exception(sprintf('❌ %s does not have a template.', $component->getI));
+    }
+    $source = $this->twig->getLoader()->getSourceContext($template_path);
+    try {
+      // Need to load as a component.
+      $node_tree = $this->twig->parse($this->twig->tokenize($source));
+      $node = $node_tree->getNode('blocks');
+    }
+    catch (Error $error) {
+      throw new \Exception("❌ Error parsing twig file: " . $error->getMessage(), $error->getCode(), $error);
+    }
+
+    $metadata = $component->metadata;
+    if (!$metadata->mandatorySchemas) {
+      return;
+    }
+    $slot_definitions = $metadata->slots;
+    $ids_available = array_keys($slot_definitions);
+    $undocumented_ids = [];
+    try {
+      $it = $node->getIterator();
+    }
+    catch (\Exception) {
+      return;
+    }
+    if ($it instanceof \SeekableIterator) {
+      while ($it->valid()) {
+        $provided_id = $it->key();
+        if (!in_array($provided_id, $ids_available, TRUE)) {
+          $undocumented_ids[] = $provided_id;
+        }
+        $it->next();
+      }
+    }
+    // Now build the error message.
+    $error_messages = [];
+    if (!empty($undocumented_ids)) {
+      $error_messages[] = sprintf(
+        'We found an unexpected slot that is not declared: [%s]. Declare them in "%s.component.yml".',
+        implode(', ', $undocumented_ids),
+        $component->machineName
+      );
+    }
+    if (!empty($error_messages)) {
+      $message = implode("\n", $error_messages);
+      throw new InvalidComponentException($message);
+    }
+  }
+
+}
diff --git a/web/modules/custom/sdc_validator/tests/src/Kernel/ValidateComponentCommandTest.php b/web/modules/custom/sdc_validator/tests/src/Kernel/ValidateComponentCommandTest.php
new file mode 100644
index 000000000..8980d2c68
--- /dev/null
+++ b/web/modules/custom/sdc_validator/tests/src/Kernel/ValidateComponentCommandTest.php
@@ -0,0 +1,279 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Drupal\Tests\sdc_validator\Kernel;
+
+use Drupal\Core\Template\TwigEnvironment;
+use Drupal\Core\Theme\ComponentPluginManager;
+use Drupal\sdc_validator\Commands\ValidateComponentCommand;
+use Drupal\KernelTests\KernelTestBase;
+use Drupal\Core\File\FileSystemInterface;
+use Symfony\Component\Console\Output\BufferedOutput;
+
+/**
+ * Tests the ValidateComponentCommand functionality.
+ *
+ * @group sdc_validator
+ */
+class ValidateComponentCommandTest extends KernelTestBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  protected static $modules = [
+    'sdc_validator',
+  ];
+
+  /**
+   * The validate component command instance.
+   */
+  protected ValidateComponentCommand $command;
+
+  /**
+   * The test components directory.
+   */
+  protected string $testComponentsDir;
+
+  /**
+   * The file system service.
+   */
+  protected FileSystemInterface $fileSystem;
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function setUp(): void {
+    parent::setUp();
+
+    // Get file system service.
+    $this->fileSystem = $this->container->get('file_system');
+
+    $this->testComponentsDir = $this->fileSystem->getTempDirectory() . '/test_components_' . uniqid();
+    $this->fileSystem->mkdir($this->testComponentsDir);
+
+    $this->command = new ValidateComponentCommandMock($this->container->get('plugin.manager.sdc'), $this->container->get('twig'));
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function tearDown(): void {
+    // Clean up test directory.
+    if ($this->testComponentsDir && is_dir($this->testComponentsDir)) {
+      $this->fileSystem->deleteRecursive($this->testComponentsDir);
+    }
+    parent::tearDown();
+  }
+
+  /**
+   * Tests validation of a valid component.
+   */
+  public function testValidComponent(): void {
+    // Create a valid component file.
+    file_put_contents(
+      $this->testComponentsDir . '/valid.component.yml',
+      <<<YAML
+\$schema: https://git.drupalcode.org/project/drupal/-/raw/HEAD/core/assets/schemas/v1/metadata.schema.json
+name: Valid Component
+status: stable
+description: A valid test component
+props:
+  type: object
+  properties:
+    theme:
+      type: string
+      enum:
+        - light
+        - dark
+slots:
+  content:
+    title: Content
+    description: Main content slot
+YAML
+    );
+
+    $this->command->validateComponentDefinitions($this->testComponentsDir);
+    $output = $this->command->getOutputBuffer();
+
+    $this->assertStringContainsString('✅ 1 components are valid', $output);
+    $this->assertStringContainsString('✨ All components are valid', $output);
+  }
+
+  /**
+   * Tests validation with invalid YAML syntax.
+   */
+  public function testInvalidYamlSyntax(): void {
+    // Create component with invalid YAML.
+    file_put_contents(
+      $this->testComponentsDir . '/invalid-yaml.component.yml',
+      <<<YAML
+\$schema: https://git.drupalcode.org/project/drupal/-/raw/HEAD/core/assets/schemas/v1/metadata.schema.json
+name: Invalid YAML Component
+status: stable
+props:
+  type: object
+  properties:
+    attributes:
+      type: string
+      test
+      title: Attributes
+slots:
+  content:
+    title: Content
+YAML
+    );
+
+    $this->expectException(\Exception::class);
+    $this->expectExceptionMessage('Component validation failed.');
+
+    try {
+      $this->command->validateComponentDefinitions($this->testComponentsDir);
+    }
+    catch (\Exception $exception) {
+      $output = $this->command->getOutputBuffer();
+      $this->assertStringContainsString('Unable to parse at line', $output);
+      throw $exception;
+    }
+  }
+
+  /**
+   * Tests validation with empty slots property.
+   */
+  public function testEmptySlotsProperty(): void {
+    // Create component with empty slots.
+    file_put_contents(
+      $this->testComponentsDir . '/empty-slots.component.yml',
+      <<<YAML
+\$schema: https://git.drupalcode.org/project/drupal/-/raw/HEAD/core/assets/schemas/v1/metadata.schema.json
+name: Empty Slots Component
+status: stable
+props:
+  type: object
+slots:
+YAML
+    );
+
+    $this->expectException(\Exception::class);
+    $this->expectExceptionMessage('Component validation failed.');
+
+    try {
+      $this->command->validateComponentDefinitions($this->testComponentsDir);
+    }
+    catch (\Exception $exception) {
+      $output = $this->command->getOutputBuffer();
+      $this->assertStringContainsString('[slots] NULL value found, but an object is required', $output);
+      throw $exception;
+    }
+  }
+
+  /**
+   * Tests validation with non-existent directory.
+   */
+  public function testNonExistentDirectory(): void {
+    $this->expectException(\Exception::class);
+    $this->expectExceptionMessage('Components directory not found');
+    $this->command->validateComponentDefinitions('/non/existent/path');
+  }
+
+  /**
+   * Tests validation with directory containing no component files.
+   */
+  public function testNoComponentFiles(): void {
+    // Create empty directory.
+    $empty_dir = $this->testComponentsDir . '/empty';
+    $this->fileSystem->mkdir($empty_dir);
+
+    $this->expectException(\Exception::class);
+    $this->expectExceptionMessage('No component definition files found');
+    $this->command->validateComponentDefinitions($empty_dir);
+  }
+
+  /**
+   * Tests validation with multiple components including failures.
+   */
+  public function testMultipleComponentsWithFailures(): void {
+    // Create valid component.
+    file_put_contents(
+      $this->testComponentsDir . '/valid.component.yml',
+      <<<YAML
+\$schema: https://git.drupalcode.org/project/drupal/-/raw/HEAD/core/assets/schemas/v1/metadata.schema.json
+name: Valid Component
+status: stable
+description: A valid component
+props:
+  type: object
+slots:
+  content:
+    title: Content
+YAML
+    );
+
+    // Create invalid component.
+    file_put_contents(
+      $this->testComponentsDir . '/invalid.component.yml',
+      <<<YAML
+\$schema: https://git.drupalcode.org/project/drupal/-/raw/HEAD/core/assets/schemas/v1/metadata.schema.json
+name: Invalid Component
+status: stable
+props:
+  type: object
+  properties:
+    test
+      invalid: yaml
+slots:
+YAML
+    );
+
+    $this->expectException(\Exception::class);
+    $this->expectExceptionMessage('Component validation failed.');
+
+    try {
+      $this->command->validateComponentDefinitions($this->testComponentsDir);
+    }
+    catch (\Exception $exception) {
+      $output = $this->command->getOutputBuffer();
+      // Should show 1 valid component.
+      $this->assertStringContainsString('✅ 1 components are valid', $output);
+      // Should show the failure.
+      $this->assertStringContainsString('Failed components:', $output);
+      $this->assertStringContainsString('Mapping values are not allowed', $output);
+      throw $exception;
+    }
+  }
+
+}
+
+/**
+ * Mock class for ValidateComponentCommand that captures output.
+ */
+class ValidateComponentCommandMock extends ValidateComponentCommand {
+
+  /**
+   * Output buffer.
+   */
+  private readonly BufferedOutput $outputBuffer;
+
+  /**
+   * {@inheritdoc}
+   */
+  public function __construct(protected ComponentPluginManager $componentPluginManager, protected TwigEnvironment $twig) {
+    parent::__construct($componentPluginManager, $twig);
+    $this->outputBuffer = new BufferedOutput();
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function output() {
+    return $this->outputBuffer;
+  }
+
+  /**
+   * Get the output buffer content.
+   */
+  public function getOutputBuffer(): string {
+    return $this->outputBuffer->fetch();
+  }
+
+}