diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 1303507f9..39e1bc38a 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -15,8 +15,18 @@ jobs:
   build:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
-      - uses: ./.github/actions/setup
+      - name: Checkout branch
+        uses: actions/checkout@v4
+        uses: ./.github/actions/setup
+        with:
+          ref: 'main'
+          path: br-base
+      - name: Bundle size report
+        uses: nejcm/bundle-size-reporter-action@v1.2.1
+        with:
+          paths: 'packages/*'
+          onlyDiff: 'true'
+          filter: '.*\\.min\\.js'
 
       - name: Check all package.json's and tsconfig.json's are in sync.
         run: |