diff --git a/apps/api/pyproject.toml b/apps/api/pyproject.toml
index 9e6b8bd..7cfef33 100644
--- a/apps/api/pyproject.toml
+++ b/apps/api/pyproject.toml
@@ -41,7 +41,7 @@ dev = [
     # Pinned: a floating ruff means CI (fresh install → newest) enables lint rules a
     # stale local ruff hasn't, so `ruff check` is green locally but red in CI. Bump
     # deliberately after fixing any new findings locally.
-    "ruff==0.15.20",
+    "ruff==0.15.21",
     "mypy==2.1.0",
     "pip-audit==2.10.1",
     "uv==0.11.15",
diff --git a/apps/api/sandbox-requirements.in b/apps/api/sandbox-requirements.in
index c34a8b6..9655c4b 100644
--- a/apps/api/sandbox-requirements.in
+++ b/apps/api/sandbox-requirements.in
@@ -1,5 +1,5 @@
 pytest==9.1.1
-ruff==0.15.20
+ruff==0.15.21
 mypy==2.1.0
 openpyxl==3.1.5
 python-docx==1.2.0