diff --git a/python/sglang/srt/managers/request_metrics_exporter.py b/python/sglang/srt/managers/request_metrics_exporter.py
index 95f1fda8f..2ecc655b7 100644
--- a/python/sglang/srt/managers/request_metrics_exporter.py
+++ b/python/sglang/srt/managers/request_metrics_exporter.py
@@ -12,6 +12,10 @@ from sglang.srt.server_args import ServerArgs
 
 logger = logging.getLogger(__name__)
 
+# Fields that should always be excluded from request parameters
+# because they contain non-JSON-serializable objects (e.g., ImageData, tensors)
+ALWAYS_EXCLUDE_FIELDS = {"image_data", "video_data", "audio_data", "input_embeds"}
+
 
 class RequestMetricsExporter(ABC):
     """Abstract base class for exporting request-level performance metrics to a data destination."""
@@ -35,7 +39,11 @@ class RequestMetricsExporter(ABC):
         request_params = {}
         for field in dataclasses.fields(obj):
             field_name = field.name
-            if field_name not in self.obj_skip_names:
+            # Skip fields in obj_skip_names or fields that are always excluded (not JSON serializable)
+            if (
+                field_name not in self.obj_skip_names
+                and field_name not in ALWAYS_EXCLUDE_FIELDS
+            ):
                 value = getattr(obj, field_name)
                 # Convert to serializable format
                 if value is not None: