Next.js "Export encountered errors" - Fix in CI

By Kaveh Alemi·Latchkey

Static export renders each page at build time. If a page throws while rendering - a runtime-only API, an undefined value, or a failing fetch - the export lists the offending paths and fails.

What this error means

The build prints Export encountered errors on following paths: followed by the routes that threw.

Error: Export encountered errors on following paths:
  /product/[id]: /product/42
  /blog/[slug]: /blog/hello-world

> Build error occurred

Common causes

Runtime-only code during export

A page touches window/document or a request-time API during static rendering, which has no browser or request.

Build-time data fetch failed

A getStaticProps/generateStaticParams fetch returned an error or undefined, so the page render threw.

How to fix it

Guard browser-only code

1. Move browser APIs into effects, or guard with a typeof check.

useEffect(() => {
  const w = window.innerWidth;
}, []);

Make build-time fetches robust

1. Handle non-OK responses and return safe fallbacks so the render does not throw.

const res = await fetch(url);
if (!res.ok) return { notFound: true };

How to prevent it

• Keep browser-only access out of render paths used by static export.
• Treat build-time fetch failures as expected and handle them.

Frequently asked questions

Related guides

References

• Node.js documentation
• npm CLI documentation
• GitHub Actions documentation