Routes

When creating you own routes to deliver responses that will only be used to service HTMX requests, you should add _htmx_route: 'true' to the route definition. This will cause Drupal to return the simpler response described in the following section.

your_module.custom_route:
  path: '/your_module/path'
  defaults:
    _controller: '\Drupal\your_module\Controller\CustomController::method'
    _title: 'HTMX markup'
  requirements:
    _permission: 'access content'
  options:
    _htmx_route: true

Response

For performance and simplicity we make use of the core page rendering variant Drupal\Core\Render\Plugin\DisplayVariant\SimplePageVariant. This variant does not render any blocks, but only system messages and the main content.