diff --git a/test/playwright/tests/helpers/ensure-build.ts b/test/playwright/tests/helpers/ensure-build.ts
new file mode 100644
index 00000000..15691867
--- /dev/null
+++ b/test/playwright/tests/helpers/ensure-build.ts
@@ -0,0 +1,34 @@
+import { spawnSync } from 'node:child_process';
+import path from 'node:path';
+
+let didBuild = false;
+
+/**
+ * Ensure the Editor.js bundle is freshly built before running Playwright tests.
+ *
+ * Necessary because the Playwright fixtures load the UMD bundle directly from the dist folder.
+ * Without rebuilding we might exercise stale code that doesn't match the current TypeScript sources.
+ */
+export const ensureEditorBundleBuilt = (): void => {
+  if (didBuild) {
+    return;
+  }
+
+  const projectRoot = path.resolve(__dirname, '../../../..');
+  const result = spawnSync('yarn', [ 'build:test' ], {
+    cwd: projectRoot,
+    stdio: 'inherit',
+    shell: process.platform === 'win32',
+  });
+
+  if (result.error) {
+    throw result.error;
+  }
+
+  if (result.status !== 0) {
+    throw new Error(`Building Editor.js for Playwright failed with exit code ${result.status ?? 'unknown'}.`);
+  }
+
+  didBuild = true;
+};
+