diff --git a/backend_api_python/app/_version.py b/backend_api_python/app/_version.py
index 76ecdf9..5e71a74 100644
--- a/backend_api_python/app/_version.py
+++ b/backend_api_python/app/_version.py
@@ -14,6 +14,7 @@ from pathlib import Path
 
 FALLBACK_VERSION = "0.0.0-dev"
 TAG_REF_PREFIX = "refs/tags/"
+BRANCH_REF_PREFIX = "refs/heads/"
 
 
 def normalize_version(value: object) -> str:
@@ -23,6 +24,8 @@ def normalize_version(value: object) -> str:
         return ""
     if text.startswith(TAG_REF_PREFIX):
         text = text[len(TAG_REF_PREFIX) :]
+    elif text.startswith(BRANCH_REF_PREFIX):
+        text = text[len(BRANCH_REF_PREFIX) :]
     if text.startswith("v") and len(text) > 1 and text[1].isdigit():
         text = text[1:]
     return text
diff --git a/backend_api_python/scripts/export_openapi.py b/backend_api_python/scripts/export_openapi.py
index 562acdd..6dbd76a 100644
--- a/backend_api_python/scripts/export_openapi.py
+++ b/backend_api_python/scripts/export_openapi.py
@@ -46,6 +46,13 @@ def export_spec(output: Path, fmt: str) -> None:
 
     from app.openapi.register import enrich_spec
     spec_dict = enrich_spec(spec_dict)
+    # Runtime build/version metadata is intentionally excluded from the
+    # committed spec. CI exports from branch refs while release images export
+    # from tags, so keeping this field would make openapi.yaml drift even when
+    # the API surface has not changed.
+    info = spec_dict.get("info")
+    if isinstance(info, dict):
+        info.pop("x-api-app-version", None)
 
     output.parent.mkdir(parents=True, exist_ok=True)
 
diff --git a/backend_api_python/tests/test_app_version.py b/backend_api_python/tests/test_app_version.py
index 8b95c17..13439cc 100644
--- a/backend_api_python/tests/test_app_version.py
+++ b/backend_api_python/tests/test_app_version.py
@@ -25,6 +25,7 @@ def local_temp_dir() -> Iterator[Path]:
 def test_normalize_version_accepts_common_tag_formats():
     assert normalize_version("v3.0.23") == "3.0.23"
     assert normalize_version("refs/tags/v3.0.23") == "3.0.23"
+    assert normalize_version("refs/heads/main") == "main"
     assert normalize_version("3.0.23") == "3.0.23"
 
 
@@ -73,6 +74,16 @@ def test_floating_tag_falls_back_to_version_file():
         )
 
 
+def test_branch_ref_falls_back_to_version_file():
+    with local_temp_dir() as tmp_path:
+        (tmp_path / "VERSION").write_text("3.0.22\n", encoding="utf-8")
+
+        assert (
+            resolve_app_version({"GITHUB_REF": "refs/heads/main"}, repo_root=tmp_path, app_root=tmp_path, use_git=False)
+            == "3.0.22"
+        )
+
+
 def test_missing_sources_return_dev_fallback():
     with local_temp_dir() as tmp_path:
         assert resolve_app_version({}, repo_root=tmp_path, app_root=tmp_path, use_git=False) == FALLBACK_VERSION
diff --git a/backend_api_python/tests/test_openapi.py b/backend_api_python/tests/test_openapi.py
index 4f17ad1..c73ce63 100644
--- a/backend_api_python/tests/test_openapi.py
+++ b/backend_api_python/tests/test_openapi.py
@@ -70,4 +70,5 @@ def test_export_script_writes_yaml(tmp_path):
     )
     loaded = yaml.safe_load(out.read_text(encoding="utf-8"))
     assert loaded["openapi"].startswith("3.")
+    assert "x-api-app-version" not in loaded.get("info", {})
     assert "/health" in loaded["paths"]
diff --git a/docs/api/openapi.yaml b/docs/api/openapi.yaml
index d955457..16bd95a 100644
--- a/docs/api/openapi.yaml
+++ b/docs/api/openapi.yaml
@@ -6,7 +6,6 @@ info:
     url: https://github.com/brokermr810/quantdinger
   license:
     name: See repository LICENSE
-  x-api-app-version: 3.0.22
   title: QuantDinger Web API
   version: 1.0.0
 components: