diff --git a/lib/Alchemy/Phrasea/Controller/Api/V3/V3Controller.php b/lib/Alchemy/Phrasea/Controller/Api/V3/V3Controller.php
new file mode 100644
index 0000000000..fe865f41c2
--- /dev/null
+++ b/lib/Alchemy/Phrasea/Controller/Api/V3/V3Controller.php
@@ -0,0 +1,76 @@
+<?php
+
+namespace Alchemy\Phrasea\Controller\Api\V3;
+
+use Alchemy\Phrasea\Controller\Api\Result;
+use Alchemy\Phrasea\Controller\Controller;
+use Symfony\Component\HttpFoundation\Request;
+
+class V3Controller extends Controller
+{
+    public function getDataboxSubdefsAction(Request $request)
+    {
+        if (!empty($request->attributes->get('databox_id'))) {
+            $ret = [
+                'databoxes' => $this->listSubdefsStructure([$this->findDataboxById($request->attributes->get('databox_id'))])
+            ];
+        } else {
+            $acl = $this->getAclForUser($this->getAuthenticatedUser());
+
+            // ensure can see databox structure
+            $ret = [
+                'databoxes' => $this->listSubdefsStructure($acl->get_granted_sbas([\ACL::BAS_MODIFY_STRUCT]))
+            ];
+        }
+
+        return Result::create($request, $ret)->createResponse();
+    }
+
+    /**
+     * List the subdef structure of databoxes
+     * @param array $databoxes
+     * @return array
+     * @throws \Exception
+     */
+    private function listSubdefsStructure(array $databoxes)
+    {
+        $ret = [];
+
+        /** @var \databox $databox */
+        foreach ($databoxes as $databox) {
+            $databoxId = $databox->get_sbas_id();
+            $subdefStructure = $databox->get_subdef_structure();
+            $subdefs = [];
+            foreach ($subdefStructure as $subGroup) {
+                /** @var \databox_subdef $sub */
+                foreach ($subGroup->getIterator() as $sub) {
+                    $opt = [];
+                    $data = [
+                        'name'             => $sub->get_name(),
+                        'databox_id'       => $databoxId,
+                        'class'            => $sub->get_class(),
+                        'preset'           => $sub->get_preset(),
+                        'downloadable'     => $sub->isDownloadable(),
+                        'devices'          => $sub->getDevices(),
+                        'labels'           => [
+                            'fr' => $sub->get_label('fr'),
+                            'en' => $sub->get_label('en'),
+                            'de' => $sub->get_label('de'),
+                            'nl' => $sub->get_label('nl'),
+                        ],
+                    ];
+                    $options = $sub->getOptions();
+                    foreach ($options as $option) {
+                        $opt[$option->getName()] = $option->getValue();
+                    }
+                    $data['options'] = $opt;
+                    $subdefs[$subGroup->getName()][$sub->get_name()] = $data;
+                }
+            }
+            $ret[$databoxId]['databox_id']  = $databoxId;
+            $ret[$databoxId]['subdefs']     = $subdefs;
+        }
+
+        return $ret;
+    }
+}
diff --git a/lib/Alchemy/Phrasea/ControllerProvider/Api/V3.php b/lib/Alchemy/Phrasea/ControllerProvider/Api/V3.php
index 011000495d..e7797eaf92 100644
--- a/lib/Alchemy/Phrasea/ControllerProvider/Api/V3.php
+++ b/lib/Alchemy/Phrasea/ControllerProvider/Api/V3.php
@@ -4,6 +4,7 @@ namespace Alchemy\Phrasea\ControllerProvider\Api;
 
 use Alchemy\Phrasea\Application as PhraseaApplication;
 use Alchemy\Phrasea\Controller\Api\V1Controller;
+use Alchemy\Phrasea\Controller\Api\V3\V3Controller;
 use Alchemy\Phrasea\Controller\Api\V3\V3RecordController;
 use Alchemy\Phrasea\Controller\Api\V3\V3ResultHelpers;
 use Alchemy\Phrasea\Controller\Api\V3\V3SearchController;
@@ -53,6 +54,9 @@ class V3 extends Api implements ControllerProviderInterface, ServiceProviderInte
         $app['controller.api.v3.stories'] = $app->share(function (PhraseaApplication $app) {
             return (new V3StoriesController($app));
         });
+        $app['controller.api.v3'] = $app->share(function (PhraseaApplication $app) {
+            return (new V3Controller($app));
+        });
     }
 
     public function boot(Application $app)
@@ -150,6 +154,16 @@ class V3 extends Api implements ControllerProviderInterface, ServiceProviderInte
             $controllers->post('/subdefs_service/', 'controller.api.v3.subdefs_service:indexAction_POST');
         }
 
+        /**
+         * @uses V3Controller::getDataboxSubdefsAction()
+         */
+        $controllers->get('/databoxes/{databox_id}/subdefs/', 'controller.api.v3:getDataboxSubdefsAction')
+            ->before('controller.api.v1:ensureAccessToDatabox')
+            ->before('controller.api.v1:ensureCanSeeDataboxStructure')
+            ->assert('databox_id', '\d+');
+
+        $controllers->get('/databoxes/subdefs/', 'controller.api.v3:getDataboxSubdefsAction');
+
         return $controllers;
     }