diff --git a/api/core/workflow/nodes/http_request/executor.py b/api/core/workflow/nodes/http_request/executor.py
index 94b6d4c8d..c9f7fa122 100644
--- a/api/core/workflow/nodes/http_request/executor.py
+++ b/api/core/workflow/nodes/http_request/executor.py
@@ -276,7 +276,8 @@ class Executor:
                     encoded_credentials = credentials
                 headers[authorization.config.header] = f"Basic {encoded_credentials}"
             elif self.auth.config.type == "custom":
-                headers[authorization.config.header] = authorization.config.api_key or ""
+                if authorization.config.header and authorization.config.api_key:
+                    headers[authorization.config.header] = authorization.config.api_key
 
         # Handle Content-Type for multipart/form-data requests
         # Fix for issue #23829: Missing boundary when using multipart/form-data
diff --git a/api/tests/integration_tests/workflow/nodes/test_http.py b/api/tests/integration_tests/workflow/nodes/test_http.py
index 344539d51..f7bb7c460 100644
--- a/api/tests/integration_tests/workflow/nodes/test_http.py
+++ b/api/tests/integration_tests/workflow/nodes/test_http.py
@@ -160,6 +160,177 @@ def test_custom_authorization_header(setup_http_mock):
 
     assert "?A=b" in data
     assert "X-Header: 123" in data
+    # Custom authorization header should be set (may be masked)
+    assert "X-Auth:" in data
+
+
+@pytest.mark.parametrize("setup_http_mock", [["none"]], indirect=True)
+def test_custom_auth_with_empty_api_key_does_not_set_header(setup_http_mock):
+    """Test: In custom authentication mode, when the api_key is empty, no header should be set."""
+    from core.workflow.entities.variable_pool import VariablePool
+    from core.workflow.nodes.http_request.entities import (
+        HttpRequestNodeAuthorization,
+        HttpRequestNodeData,
+        HttpRequestNodeTimeout,
+    )
+    from core.workflow.nodes.http_request.executor import Executor
+    from core.workflow.system_variable import SystemVariable
+
+    # Create variable pool
+    variable_pool = VariablePool(
+        system_variables=SystemVariable(user_id="test", files=[]),
+        user_inputs={},
+        environment_variables=[],
+        conversation_variables=[],
+    )
+
+    # Create node data with custom auth and empty api_key
+    node_data = HttpRequestNodeData(
+        title="http",
+        desc="",
+        url="http://example.com",
+        method="get",
+        authorization=HttpRequestNodeAuthorization(
+            type="api-key",
+            config={
+                "type": "custom",
+                "api_key": "",  # Empty api_key
+                "header": "X-Custom-Auth",
+            },
+        ),
+        headers="",
+        params="",
+        body=None,
+        ssl_verify=True,
+    )
+
+    # Create executor
+    executor = Executor(
+        node_data=node_data, timeout=HttpRequestNodeTimeout(connect=10, read=30, write=10), variable_pool=variable_pool
+    )
+
+    # Get assembled headers
+    headers = executor._assembling_headers()
+
+    # When api_key is empty, the custom header should NOT be set
+    assert "X-Custom-Auth" not in headers
+
+
+@pytest.mark.parametrize("setup_http_mock", [["none"]], indirect=True)
+def test_bearer_authorization_with_custom_header_ignored(setup_http_mock):
+    """
+    Test that when switching from custom to bearer authorization,
+    the custom header settings don't interfere with bearer token.
+    This test verifies the fix for issue #23554.
+    """
+    node = init_http_node(
+        config={
+            "id": "1",
+            "data": {
+                "title": "http",
+                "desc": "",
+                "method": "get",
+                "url": "http://example.com",
+                "authorization": {
+                    "type": "api-key",
+                    "config": {
+                        "type": "bearer",
+                        "api_key": "test-token",
+                        "header": "",  # Empty header - should default to Authorization
+                    },
+                },
+                "headers": "",
+                "params": "",
+                "body": None,
+            },
+        }
+    )
+
+    result = node._run()
+    assert result.process_data is not None
+    data = result.process_data.get("request", "")
+
+    # In bearer mode, should use Authorization header (value is masked with *)
+    assert "Authorization: " in data
+    # Should contain masked Bearer token
+    assert "*" in data
+
+
+@pytest.mark.parametrize("setup_http_mock", [["none"]], indirect=True)
+def test_basic_authorization_with_custom_header_ignored(setup_http_mock):
+    """
+    Test that when switching from custom to basic authorization,
+    the custom header settings don't interfere with basic auth.
+    This test verifies the fix for issue #23554.
+    """
+    node = init_http_node(
+        config={
+            "id": "1",
+            "data": {
+                "title": "http",
+                "desc": "",
+                "method": "get",
+                "url": "http://example.com",
+                "authorization": {
+                    "type": "api-key",
+                    "config": {
+                        "type": "basic",
+                        "api_key": "user:pass",
+                        "header": "",  # Empty header - should default to Authorization
+                    },
+                },
+                "headers": "",
+                "params": "",
+                "body": None,
+            },
+        }
+    )
+
+    result = node._run()
+    assert result.process_data is not None
+    data = result.process_data.get("request", "")
+
+    # In basic mode, should use Authorization header (value is masked with *)
+    assert "Authorization: " in data
+    # Should contain masked Basic credentials
+    assert "*" in data
+
+
+@pytest.mark.parametrize("setup_http_mock", [["none"]], indirect=True)
+def test_custom_authorization_with_empty_api_key(setup_http_mock):
+    """
+    Test that custom authorization doesn't set header when api_key is empty.
+    This test verifies the fix for issue #23554.
+    """
+    node = init_http_node(
+        config={
+            "id": "1",
+            "data": {
+                "title": "http",
+                "desc": "",
+                "method": "get",
+                "url": "http://example.com",
+                "authorization": {
+                    "type": "api-key",
+                    "config": {
+                        "type": "custom",
+                        "api_key": "",  # Empty api_key
+                        "header": "X-Custom-Auth",
+                    },
+                },
+                "headers": "",
+                "params": "",
+                "body": None,
+            },
+        }
+    )
+
+    result = node._run()
+    assert result.process_data is not None
+    data = result.process_data.get("request", "")
+
+    # Custom header should NOT be set when api_key is empty
+    assert "X-Custom-Auth:" not in data
 
 
 @pytest.mark.parametrize("setup_http_mock", [["none"]], indirect=True)
@@ -239,6 +410,7 @@ def test_json(setup_http_mock):
     assert "X-Header: 123" in data
 
 
+@pytest.mark.parametrize("setup_http_mock", [["none"]], indirect=True)
 def test_x_www_form_urlencoded(setup_http_mock):
     node = init_http_node(
         config={
@@ -285,6 +457,7 @@ def test_x_www_form_urlencoded(setup_http_mock):
     assert "X-Header: 123" in data
 
 
+@pytest.mark.parametrize("setup_http_mock", [["none"]], indirect=True)
 def test_form_data(setup_http_mock):
     node = init_http_node(
         config={
@@ -334,6 +507,7 @@ def test_form_data(setup_http_mock):
     assert "X-Header: 123" in data
 
 
+@pytest.mark.parametrize("setup_http_mock", [["none"]], indirect=True)
 def test_none_data(setup_http_mock):
     node = init_http_node(
         config={
@@ -366,6 +540,7 @@ def test_none_data(setup_http_mock):
     assert "123123123" not in data
 
 
+@pytest.mark.parametrize("setup_http_mock", [["none"]], indirect=True)
 def test_mock_404(setup_http_mock):
     node = init_http_node(
         config={
@@ -394,6 +569,7 @@ def test_mock_404(setup_http_mock):
     assert "Not Found" in resp.get("body", "")
 
 
+@pytest.mark.parametrize("setup_http_mock", [["none"]], indirect=True)
 def test_multi_colons_parse(setup_http_mock):
     node = init_http_node(
         config={