diff --git a/openfga_sdk/rest.py b/openfga_sdk/rest.py
index dc7c701..d227e6a 100644
--- a/openfga_sdk/rest.py
+++ b/openfga_sdk/rest.py
@@ -27,6 +27,7 @@
     RateLimitExceededError,
     ServiceException,
     UnauthorizedException,
+    ValidationException,
 )
 
 logger = logging.getLogger(__name__)
@@ -174,6 +175,9 @@ async def request(
             logger.debug("response body: %s", r.data)
 
             if not 200 <= r.status <= 299:
+                if r.status == 400:
+                    raise ValidationException(http_resp=r)
+
                 if r.status == 401:
                     raise UnauthorizedException(http_resp=r)
 
diff --git a/openfga_sdk/sync/rest.py b/openfga_sdk/sync/rest.py
index 0f07412..afad041 100644
--- a/openfga_sdk/sync/rest.py
+++ b/openfga_sdk/sync/rest.py
@@ -24,6 +24,7 @@
     ApiValueError,
     ForbiddenException,
     NotFoundException,
+    RateLimitExceededError,
     ServiceException,
     UnauthorizedException,
     ValidationException,
@@ -252,6 +253,9 @@ def request(
             if r.status == 404:
                 raise NotFoundException(http_resp=r)
 
+            if r.status == 429:
+                raise RateLimitExceededError(http_resp=r)
+
             if 500 <= r.status <= 599:
                 raise ServiceException(http_resp=r)