diff --git a/.github/dependabot.yml b/.github/dependabot.yml
new file mode 100644
index 0000000..c4528d0
--- /dev/null
+++ b/.github/dependabot.yml
@@ -0,0 +1,39 @@
+# Dependency updates for every ecosystem this repository ships.
+#
+# Each ecosystem is ONE catch-all group covering minor, patch and major, with
+# open-pull-requests-limit 1, so a week yields at most one pull request per
+# ecosystem instead of one per dependency. Dependabot cannot group across
+# ecosystems, so the number of entries below is the floor on weekly PRs.
+#
+# The github-actions entry exists because every action is pinned by commit SHA;
+# nothing else would ever move those pins.
+version: 2
+
+updates:
+  - package-ecosystem: pip
+    directory: /
+    schedule:
+      interval: weekly
+    open-pull-requests-limit: 1
+    groups:
+      pip:
+        patterns:
+          - "*"
+        update-types:
+          - minor
+          - patch
+          - major
+
+  - package-ecosystem: github-actions
+    directory: /
+    schedule:
+      interval: weekly
+    open-pull-requests-limit: 1
+    groups:
+      github-actions:
+        patterns:
+          - "*"
+        update-types:
+          - minor
+          - patch
+          - major
diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index dd5874d..e1c9f88 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -12,8 +12,8 @@ jobs:
       matrix:
         python-version: ["3.10", "3.12"]
     steps:
-      - uses: actions/checkout@v4
-      - uses: actions/setup-python@v5
+      - uses: actions/checkout@11d5960a326750d5838078e36cf38b85af677262 # v4
+      - uses: actions/setup-python@a26af69be951a213d495a4c3e4e4022e16d87065 # v5
         with:
           python-version: ${{ matrix.python-version }}
       - run: python -m pip install --upgrade pip