feat(build): add bundle-api script for Vercel serverless API pre-bundling

Author: hotlong

apps/studio/package.json

@@ -69,7 +69,8 @@
     "tailwindcss": "^4.2.2",
     "typescript": "^5.0.0",
     "vite": "^8.0.1",
-    "vitest": "^4.1.0"
+    "vitest": "^4.1.0",
+    "esbuild": "^0.25.0"
   },
   "msw": {
     "workerDirectory": [

apps/studio/scripts/bundle-api.mjs

@@ -0,0 +1,46 @@
+/**
+ * Pre-bundles the Vercel serverless API function.
+ *
+ * Vercel's @vercel/node builder resolves pnpm workspace packages via symlinks,
+ * which can cause esbuild to resolve to TypeScript source files rather than
+ * compiled dist output — producing ERR_MODULE_NOT_FOUND at runtime.
+ *
+ * This script bundles api/index.ts with all @objectstack/* workspace packages
+ * inlined, while keeping third-party npm packages external (they resolve
+ * normally from node_modules at runtime).
+ *
+ * Run from the apps/studio directory during the Vercel build step.
+ */
+
+import { build } from 'esbuild';
+import { unlinkSync } from 'node:fs';
+
+await build({
+  entryPoints: ['api/index.ts'],
+  bundle: true,
+  platform: 'node',
+  format: 'esm',
+  target: 'es2020',
+  outfile: 'api/index.mjs',
+  sourcemap: true,
+  // Maintain proper __dirname / import.meta.url behaviour
+  define: {},
+  plugins: [{
+    name: 'externalize-non-workspace',
+    setup(build) {
+      build.onResolve({ filter: /.*/ }, (args) => {
+        // Bundle relative imports (../src/lib/*, ../objectstack.config.js, etc.)
+        if (args.path.startsWith('.') || args.path.startsWith('/')) return null;
+        // Bundle @objectstack/* workspace packages inline
+        if (args.path.startsWith('@objectstack/')) return null;
+        // Externalize everything else (npm packages, node builtins)
+        return { path: args.path, external: true };
+      });
+    },
+  }],
+});
+
+// Remove the TypeScript source so Vercel only sees the compiled .mjs
+unlinkSync('api/index.ts');
+
+console.log('[bundle-api] Bundled api/index.ts → api/index.mjs');

apps/studio/vercel.json

@@ -2,7 +2,7 @@
   "$schema": "https://openapi.vercel.sh/vercel.json",
   "framework": "vite",
   "installCommand": "cd ../.. && pnpm install",
-  "buildCommand": "cd ../.. && pnpm turbo run build --filter=@objectstack/studio",
+  "buildCommand": "cd ../.. && pnpm turbo run build --filter=@objectstack/studio && cd apps/studio && node scripts/bundle-api.mjs",
   "outputDirectory": "dist",
   "build": {
     "env": {