diff --git a/Core/API/SsoAPI.class.php b/Core/API/SsoAPI.class.php
index 2c4f775..611d7df 100644
--- a/Core/API/SsoAPI.class.php
+++ b/Core/API/SsoAPI.class.php
@@ -4,6 +4,7 @@ namespace Core\API {
   
   use Core\Objects\Context;
   use Core\Objects\DatabaseEntity\SsoProvider;
+  use Core\Objects\DatabaseEntity\SsoRequest;
   use Core\Objects\DatabaseEntity\User;
 
   abstract class SsoAPI extends Request {
@@ -11,8 +12,9 @@ namespace Core\API {
       parent::__construct($context, $externalCall, $params);
     }
 
-    protected function processLogin(SsoProvider $provider, User $user, ?string $redirectUrl): bool {
+    protected function processLogin(SsoRequest $ssoRequest, User $user): bool {
       $sql = $this->context->getSQL();
+      $provider = $ssoRequest->getProvider();
       if ($user->getId() === null) {
         // user didn't exit yet. try to insert into database
         if (!$user->save($sql)) {
@@ -29,6 +31,8 @@ namespace Core\API {
         return false;
       }
 
+      $ssoRequest->invalidate($sql, $this->context->getSession());
+      $redirectUrl = $ssoRequest->getRedirectUrl();
       if (!empty($redirectUrl)) {
         $this->context->router->redirect(302, $redirectUrl);
       }
@@ -230,37 +234,18 @@ namespace Core\API\Sso {
     }
 
     protected function _execute(): bool {
-
+      $sql = $this->context->getSQL();
       $samlResponse = base64_decode($this->getParam("SAMLResponse"));
       $parsedResponse = SAMLResponse::parseResponse($this->context, $samlResponse);
+      $ssoRequest = $parsedResponse->getRequest();
       if (!$parsedResponse->wasSuccessful()) {
+        $ssoRequest?->invalidate($sql);
         return $this->createError("Error parsing SAMLResponse: " . $parsedResponse->getError());
+      } else if (!$this->processLogin($ssoRequest, $parsedResponse->getUser())) {
+        $ssoRequest->invalidate($sql);
+        return false;
       } else {
-        return $this->processLogin($parsedResponse->getProvider(), $parsedResponse->getUser(), $parsedResponse->getRedirectURL());
-      }
-
-      $sql = $this->context->getSQL();
-      $ssoProviderIdentifier = $this->getParam("provider");
-      $ssoProvider = SsoProvider::findBy(SsoProvider::createBuilder($sql, true)
-        ->whereEq("identifier", $ssoProviderIdentifier)
-        ->whereTrue("active")
-      );
-      if ($ssoProvider === false) {
-        return $this->createError("Error fetching SSO Provider: " . $sql->getLastError());
-      } else if ($ssoProvider === null) {
-        return $this->createError("SSO Provider not found");
-      }
-
-      $samlResponseEncoded = $this->getParam("SAMLResponse");
-      if (($samlResponse = @gzinflate(base64_decode($samlResponseEncoded))) === false) {
-        $samlResponse = base64_decode($samlResponseEncoded);
-      }
-
-      $parsedUser = $ssoProvider->parseResponse($this->context, $samlResponse);
-      if ($parsedUser === null) {
-        return $this->createError("Invalid SAMLResponse");
-      } else {
-        return $this->processLogin($parsedUser, $redirectUrl);
+        return true;
       }
     }
 
diff --git a/Core/Objects/DatabaseEntity/SsoRequest.class.php b/Core/Objects/DatabaseEntity/SsoRequest.class.php
index b000764..8f9b256 100644
--- a/Core/Objects/DatabaseEntity/SsoRequest.class.php
+++ b/Core/Objects/DatabaseEntity/SsoRequest.class.php
@@ -12,12 +12,22 @@ class SsoRequest extends DatabaseEntity {
 
   const SSO_REQUEST_DURABILITY = 15; // in minutes
 
+  // auto-delete sso requests after 30 days after creation
+  protected static array $entityLogConfig = [
+    "update" => false,
+    "delete" => true,
+    "insert" => true,
+    "lifetime" => 30
+  ];
+
   #[MaxLength(128)]
   #[Unique]
   private string $identifier;
 
   private SsoProvider $ssoProvider;
 
+  private ?Session $session;
+
   private \DateTime $validUntil;
 
   #[DefaultValue(false)]
@@ -30,6 +40,7 @@ class SsoRequest extends DatabaseEntity {
     $request->identifier = uuidv4();
     $request->ssoProvider = $ssoProvider;
     $request->used = false;
+    $request->session = null;
     $request->validUntil = (new \DateTime())->modify(sprintf('+%d minutes', self::SSO_REQUEST_DURABILITY));
     $request->redirectUrl = $redirectUrl;
     if ($request->save($sql)) {
@@ -59,9 +70,14 @@ class SsoRequest extends DatabaseEntity {
     return $this->ssoProvider;
   }
 
-  public function invalidate(SQL $sql) : bool {
+  public function invalidate(SQL $sql, ?Session $session = null) : bool {
     $this->used = true;
-    return $this->save($sql, ["used"]);
+    if ($session) {
+      $this->session = $session;
+      return $this->save($sql, ["used", "session"]);
+    } else {
+      return $this->save($sql, ["used"]);
+    }
   }
 
 }
\ No newline at end of file
diff --git a/Core/Objects/SSO/SAMLResponse.class.php b/Core/Objects/SSO/SAMLResponse.class.php
index 67ed0a6..a069459 100644
--- a/Core/Objects/SSO/SAMLResponse.class.php
+++ b/Core/Objects/SSO/SAMLResponse.class.php
@@ -57,7 +57,7 @@ class SAMLResponse {
     };
   }
 
-  private static function verifyNodeSignature(SsoProvider $provider, \DOMNode $signatureNode) {
+  private static function verifyNodeSignature(SsoProvider $provider, \DOMNode $signatureNode): void {
     $signedInfoNode = $signatureNode->getElementsByTagName('SignedInfo')->item(0);
     if (!$signedInfoNode) {
       throw new \Exception("SignedInfo not found in the Signature element.");
@@ -108,8 +108,6 @@ class SAMLResponse {
       return self::createError($ssoRequest, "SAMLResponse already processed");
     } else if (!$ssoRequest->isValid()) {
       return self::createError($ssoRequest, "Authentication request expired");
-    } else {
-      $ssoRequest->invalidate($sql);
     }
 
     try {
@@ -199,4 +197,8 @@ class SAMLResponse {
     return $this->request->getProvider();
   }
 
+  public function getRequest() : ?SsoRequest {
+    return $this->request;
+  }
+
 }
\ No newline at end of file