diff --git a/appinfo/database.xml b/appinfo/database.xml
index 572c9aa..ff4d751 100644
--- a/appinfo/database.xml
+++ b/appinfo/database.xml
@@ -42,12 +42,10 @@
 				<name>token</name>
 				<type>text</type>
 				<notnull>true</notnull>
-				<unique>true</unique>
 			</field>
 			<field>
 				<name>client_secret</name>
 				<type>text</type>
-				<unique>true</unique>
 			</field>
 			<field>
 				<name>requested</name>
diff --git a/controller/apicontroller.php b/controller/apicontroller.php
index 4ddba0c..a00a85b 100644
--- a/controller/apicontroller.php
+++ b/controller/apicontroller.php
@@ -49,8 +49,9 @@ class ApiController extends OCSController {
 	/** @var Defaults */
 	private $defaults;
 
-	const OCS_STATUS_PENDING = 403;
-	const OCS_STATUS_RESENT = 403;
+	const REGISTRATION_STATUS_COMPLETE = 0;
+	const REGISTRATION_STATUS_PENDING = 1;
+	const REGISTRATION_STATUS_EXISTING = 2;
 
 	public function __construct($appName,
 								IRequest $request,
@@ -103,33 +104,39 @@ class ApiController extends OCSController {
 		try {
 			/** @var Registration $registration */
 			$registration = $this->registrationService->getRegistrationForSecret($clientSecret);
-			if(!$registration->getEmailConfirmed()) {
-				throw new OCSException(
-					$this->l10n->t('Your registration is pending. Please confirm your email address.'),
-					self::OCS_STATUS_PENDING
-				);
-			} else {
-				// create account if email confirmed and not already created
-				$user = $this->registrationService->getUserAccount($registration);
-				if($user === null) {
-					$user = $this->registrationService->createAccount($registration);
-				}
-				$this->registrationService->loginUser($user->getUID(), $registration->getUsername(), $registration->getPassword(), true);
-				$appPassword = $this->registrationService->generateAppPassword($user->getUID());
-				$data = [
-					'appPassword' => $appPassword,
-					'cloudUrl' => $this->defaults->getBaseUrl()
-				];
-				$this->registrationService->deleteRegistration($registration);
-				return new DataResponse($data, Http::STATUS_OK);
-			}
 		} catch (DoesNotExistException $e) {
 			throw new OCSNotFoundException('No pending registration.');
 		}
+
+		if (!$registration->getEmailConfirmed()) {
+			return new DataResponse(
+				[
+					'registrationStatus' => self::REGISTRATION_STATUS_PENDING,
+					'message' => $this->l10n->t('Your registration is pending. Please confirm your email address.')
+				],
+				Http::STATUS_OK
+			);
+		} else {
+			// create account if email confirmed and not already created
+			$user = $this->registrationService->getUserAccount($registration);
+			if ($user === null) {
+				$user = $this->registrationService->createAccount($registration);
+			}
+			$this->registrationService->loginUser($user->getUID(), $registration->getUsername(), $registration->getPassword(), true);
+			$appPassword = $this->registrationService->generateAppPassword($user->getUID());
+			$data = [
+				'appPassword' => $appPassword,
+				'cloudUrl' => $this->defaults->getBaseUrl(),
+				'registrationStatus' => self::REGISTRATION_STATUS_COMPLETE
+			];
+			$this->registrationService->deleteRegistration($registration);
+			return new DataResponse($data, Http::STATUS_OK);
+		}
 	}
 
 	/**
 	 * @PublicPage
+	 * @AnonRateThrottle(limit=5, period=1)
 	 *
 	 * @param string $username
 	 * @param string $displayname
@@ -152,17 +159,23 @@ class ApiController extends OCSController {
 			} else {
 				$this->registrationService->generateNewToken($registration);
 				$this->mailService->sendTokenByMail($registration);
-				throw new OCSException($this->l10n->t('There is already a pending registration with this email, a new verification email has been sent to the address.'), self::OCS_STATUS_RESENT);
+				return new DataResponse(
+					[
+						'registrationStatus' => self::REGISTRATION_STATUS_EXISTING,
+						'message' => $this->l10n->t('There is already a pending registration with this email, a new verification email has been sent to the address.')
+					],
+					Http::STATUS_OK
+				);
 			}
 
 			$data['message'] = $this->l10n->t('Your registration is pending. Please confirm your email address.');
-			$data['status'] = Registration::STATUS_PENDING;
+			$data['registrationStatus'] = self::REGISTRATION_STATUS_PENDING;
 			if($secret !== null) {
 				$data['secret'] = $secret;
 			}
 			return new DataResponse($data, Http::STATUS_OK);
 		} catch (RegistrationException $exception) {
-			throw new OCSException($exception->getMessage());
+			throw new OCSException($exception->getMessage(), $exception->getCode());
 		}
 	}
 
diff --git a/db/registration.php b/db/registration.php
index 475a600..9d8473f 100644
--- a/db/registration.php
+++ b/db/registration.php
@@ -27,9 +27,6 @@ use OCP\AppFramework\Db\Entity;
 
 class Registration extends Entity {
 
-	const STATUS_FINISHED = 0;
-	const STATUS_PENDING = 1;
-
 	public $id;
 	protected $email;
 	protected $username;
diff --git a/service/mailservice.php b/service/mailservice.php
index 7122b21..bed408c 100644
--- a/service/mailservice.php
+++ b/service/mailservice.php
@@ -79,7 +79,6 @@ class MailService {
 	 * @throws RegistrationException
 	 */
 	public function sendTokenByMail(Registration $registration) {
-		return true;
 		$link = $this->urlGenerator->linkToRoute('registration.register.verifyToken', array('token' => $registration->getToken()));
 		$link = $this->urlGenerator->getAbsoluteURL($link);
 		$template_var = [
diff --git a/service/registrationexception.php b/service/registrationexception.php
index 1035811..b3070d1 100644
--- a/service/registrationexception.php
+++ b/service/registrationexception.php
@@ -32,9 +32,10 @@ class RegistrationException extends \Exception {
 	 *
 	 * @param string $message
 	 * @param string $hint
+	 * @param int $code
 	 */
-	public function __construct($message, $hint = "") {
-		parent::__construct($message);
+	public function __construct($message, $hint = "", $code = 400) {
+		parent::__construct($message, $code);
 		$this->hint = $hint;
 	}
 
diff --git a/service/registrationservice.php b/service/registrationservice.php
index 4131f7e..9da62bb 100644
--- a/service/registrationservice.php
+++ b/service/registrationservice.php
@@ -241,7 +241,7 @@ class RegistrationService {
 		try {
 			return $this->registrationMapper->findByToken($token);
 		} catch (DoesNotExistException $exception) {
-			throw new RegistrationException($this->l10n->t('Invalid verification URL. No registration request with this verification URL is found.'));
+			throw new RegistrationException($this->l10n->t('Invalid verification URL. No registration request with this verification URL is found.', 404));
 		}
 	}