diff --git a/py/h2o_wave/hatch_build.py b/py/h2o_wave/hatch_build.py
index 06735804b8..2a2c281000 100644
--- a/py/h2o_wave/hatch_build.py
+++ b/py/h2o_wave/hatch_build.py
@@ -42,7 +42,7 @@ def initialize(self, _version, build_data):
         with open(os.path.join('h2o_wave', 'metadata.py'), 'w') as f:
             f.write(f'''
 # Generated in hatch_build.py.
-__platform__ = "{platform}"
+__platform__ = "{operating_system}"
 __arch__ = "{arch}"
         ''')