diff --git a/livekit-rtc/livekit/rtc/_ffi_client.py b/livekit-rtc/livekit/rtc/_ffi_client.py
index 91166bae..dfeb8e0f 100644
--- a/livekit-rtc/livekit/rtc/_ffi_client.py
+++ b/livekit-rtc/livekit/rtc/_ffi_client.py
@@ -193,6 +193,7 @@ def request(self, req: proto_ffi.FfiRequest) -> proto_ffi.FfiResponse:
         handle = ffi_lib.livekit_ffi_request(
             data, proto_len, ctypes.byref(resp_ptr), ctypes.byref(resp_len)
         )
+        assert handle != INVALID_HANDLE
 
         resp_data = bytes(resp_ptr[: resp_len.value])
         resp = proto_ffi.FfiResponse()