diff --git a/.gitea/workflows/build.yml b/.gitea/workflows/build.yml
index 145a5c9..856d211 100644
--- a/.gitea/workflows/build.yml
+++ b/.gitea/workflows/build.yml
@@ -16,6 +16,17 @@ jobs:
     steps:
       - name: Checkout code
         uses: actions/checkout@v4
+      - name: Install JS dependencies
+        run: npm install
+
+      - name: Build bundle
+        run: |
+          ./node_modules/.bin/esbuild \
+            build/dev/javascript/markdown2/markdown2.mjs \
+              --bundle \
+              --outfile=parser.js \
+              --format=iife \
+              --global-name=App
 
       - name: Build Gleam to JavaScript
         run: gleam build --target javascript