diff --git a/src/bloomy/configuration.py b/src/bloomy/configuration.py
index 609a278..d137141 100644
--- a/src/bloomy/configuration.py
+++ b/src/bloomy/configuration.py
@@ -109,7 +109,7 @@ def _store_api_key(self) -> None:
         config_file.parent.mkdir(parents=True, exist_ok=True)
 
         config_data = {"version": 1, "api_key": self.api_key}
-        with open(config_file, "w") as f:
+        with config_file.open("w") as f:
             yaml.dump(config_data, f)
 
     def _load_api_key(self) -> str | None:
@@ -124,7 +124,7 @@ def _load_api_key(self) -> str | None:
             return None
 
         try:
-            with open(config_file) as f:
+            with config_file.open() as f:
                 data = yaml.safe_load(f)
                 return data.get("api_key")
         except Exception:
diff --git a/tests/test_configuration.py b/tests/test_configuration.py
index 899e695..e200581 100644
--- a/tests/test_configuration.py
+++ b/tests/test_configuration.py
@@ -31,7 +31,7 @@ def test_init_with_config_file(self):
 
         with (
             patch.dict(os.environ, {"BG_API_KEY": ""}),  # Clear env var
-            patch("builtins.open", mock_open(read_data=yaml.dump(mock_yaml_data))),
+            patch("pathlib.Path.open", mock_open(read_data=yaml.dump(mock_yaml_data))),
             patch("pathlib.Path.exists", return_value=True),
         ):
             config = Configuration()
@@ -43,7 +43,7 @@ def test_init_priority_order(self):
 
         with (
             patch.dict(os.environ, {"BG_API_KEY": "env-key"}),
-            patch("builtins.open", mock_open(read_data=yaml.dump(mock_yaml_data))),
+            patch("pathlib.Path.open", mock_open(read_data=yaml.dump(mock_yaml_data))),
             patch("pathlib.Path.exists", return_value=True),
         ):
             # Direct API key takes precedence
@@ -108,7 +108,7 @@ def test_configure_api_key_with_store(self):
             mock_client_class.return_value.__enter__.return_value = mock_client
 
             with (
-                patch("builtins.open", mock_open()) as mock_file,
+                patch("pathlib.Path.open", mock_open()) as mock_file,
                 patch("pathlib.Path.mkdir"),
             ):
                 config = Configuration()
@@ -147,7 +147,7 @@ def test_load_api_key_no_file(self):
     def test_load_api_key_invalid_yaml(self):
         """Test loading API key with invalid YAML."""
         with (
-            patch("builtins.open", mock_open(read_data="invalid: yaml: content:")),
+            patch("pathlib.Path.open", mock_open(read_data="invalid: yaml: content:")),
             patch("pathlib.Path.exists", return_value=True),
             patch.dict(os.environ, {}, clear=True),
         ):
@@ -159,7 +159,7 @@ def test_config_file_location(self):
         """Test that configuration is loaded from the correct location."""
         with (
             patch("pathlib.Path.exists") as mock_exists,
-            patch("builtins.open", mock_open(read_data="api_key: test-key")),
+            patch("pathlib.Path.open", mock_open(read_data="api_key: test-key")),
             patch.dict(os.environ, {}, clear=True),
         ):
             # Initialize config which should try to load from file