diff --git a/.github/dependabot.yml b/.github/dependabot.yml
new file mode 100644
index 0000000..9a42e0c
--- /dev/null
+++ b/.github/dependabot.yml
@@ -0,0 +1,13 @@
+# Keep the three runtime deps and the CI actions patched. Dependabot opens
+# PRs; CI runs the offline test suite against them before anything merges.
+version: 2
+updates:
+  - package-ecosystem: npm
+    directory: /
+    schedule:
+      interval: weekly
+    open-pull-requests-limit: 5
+  - package-ecosystem: github-actions
+    directory: /
+    schedule:
+      interval: weekly