diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 245f78d..3b3bc3c 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -1,6 +1,12 @@
 ---
 name: Test code, build Docker image, and push to Docker Hub and GitHub Container Registry.
-on: [ push, pull_request, workflow_dispatch ]
+on:
+  push:
+    branches:
+      - master
+  pull_request:
+  workflow_dispatch:
+
 env:
   SERVE_DOMAIN: https://localhost/
   WEBHOOK_URL: ${{ secrets.WEBHOOK_URL }}