diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
new file mode 100644
index 0000000..a4bad07
--- /dev/null
+++ b/.github/workflows/ci.yml
@@ -0,0 +1,23 @@
+name: ci
+
+# Every PR runs the test suite before merge.
+on:
+  pull_request:
+  push:
+    branches: [main]
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    timeout-minutes: 10
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: erlef/setup-beam@v1
+        with:
+          elixir-version: "1.17"
+          otp-version: "27"
+
+      - run: mix deps.get
+
+      - run: mix test