diff --git a/.clang-format b/.clang-format
new file mode 100644
index 0000000..9f3e95c
--- /dev/null
+++ b/.clang-format
@@ -0,0 +1,2 @@
+---
+BasedOnStyle: Google
diff --git a/.github/format-check b/.github/format-check
new file mode 100755
index 0000000..1150e4f
--- /dev/null
+++ b/.github/format-check
@@ -0,0 +1,25 @@
+#!/bin/bash
+#   formatting using the ldmx/dev image which has clang-format in it
+
+set -o errexit
+set -o nounset
+
+if [ -z "${GITHUB_WORKSPACE+x}" ]; then
+  # we are not in github actions so we need to error out
+  echo "ERROR: this script expects to be run in GitHub actions so should not be run locally."
+  exit 1
+fi
+
+ldmx() {
+  docker \
+    run \
+    --rm \
+    --volume ${GITHUB_WORKSPACE} \
+    --env LDMX_BASE=${GITHUB_WORKSPACE} \
+    ldmx/dev:latest \
+    ${PWD}
+    $@
+}
+find include/ -type f >  ${TMPDIR:-/tmp}/files-to-format.list
+find src/ -type f     >> ${TMPDIR:-/tmp}/files-to-format.list
+ldmx clang-format --verbose -Werror --dry-run $(cat ${TMPDIR:-/tmp}/files-to-format.list)
diff --git a/.github/workflows/format-check.yml b/.github/workflows/format-check.yml
new file mode 100644
index 0000000..bfe16ba
--- /dev/null
+++ b/.github/workflows/format-check.yml
@@ -0,0 +1,14 @@
+name: Check Format
+on:
+  push:
+    branches:
+      - 'trunk'
+  pull_request:
+
+jobs:
+  clang-format:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+      - name: run format check
+        run: ./.github/format-check