diff --git a/.github/workflows/cd.yml b/.github/workflows/cd.yml
index 4d74602..b65317b 100644
--- a/.github/workflows/cd.yml
+++ b/.github/workflows/cd.yml
@@ -104,6 +104,6 @@ jobs:
           tags: ${{ steps.meta.outputs.tags }}
           labels: ${{ steps.meta.outputs.labels }}
           build-args: |
-            NEXT_PUBLIC_API_URL=${{ vars.NEXT_PUBLIC_API_URL }}
+            NEXT_PUBLIC_API_URL=${{ vars.NEXT_PUBLIC_API_URL != '' && vars.NEXT_PUBLIC_API_URL || 'http://localhost:8080/api' }}
           cache-from: type=gha
           cache-to: type=gha,mode=max
diff --git a/apps/web/Dockerfile b/apps/web/Dockerfile
index b2cba90..fcc60c3 100644
--- a/apps/web/Dockerfile
+++ b/apps/web/Dockerfile
@@ -50,9 +50,10 @@ COPY --from=deps /app/packages/tailwind-config/node_modules ./packages/tailwind-
 # Copy source code
 COPY . .
 
-# Build arguments for environment variables needed at build time
-ARG NEXT_PUBLIC_API_URL
-ENV NEXT_PUBLIC_API_URL=$NEXT_PUBLIC_API_URL
+# Build arguments for environment variables needed at build time.
+# Default keeps CI/CD builds working even when build-arg is omitted.
+ARG NEXT_PUBLIC_API_URL=http://localhost:8080/api
+ENV NEXT_PUBLIC_API_URL=${NEXT_PUBLIC_API_URL}
 
 # Build the web app (standalone output configured in next.config.ts)
 RUN pnpm --filter @repo/web build