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404 Page Isn'T Server Rendered When Using NotFound()

When calling notFound() inside a page component in Next.js App Router, the initial server response contains only client-side script tags, not the server-rendered Not Found page HTML. This affects both development and production, including static pages returning incorrect 200 status in production.

highConfidence 85%Next.js Affected V14.1.0

Origin Analysis

In Next.js App Router, the notFound() function throws a special error that is caught by the framework's error boundary, but for statically optimized pages the Not Found boundary is not rendered on the server. Instead, the client receives a generic client-side rendered shell, and the not-found UI is only hydrated on the client. This design flaw prevents server-side rendering of the 404 page and leads to incorrect HTTP status codes for static routes.

1. Create a new Next.js project using `npx create-next-app@latest`. 2. In app/page.tsx (or any page), call `notFound()` from `next/navigation`. 3. Start the app with `next dev` or `next build && next start`. 4. Open the page in a browser and inspect the network response. The response body contains only script tags, not the rendered HTML of the 404 page. 5. Compare with a non-existent route: the default Not Found page is server-rendered.

Fixing Code Block

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0xA4 1C 90 3E 77 0B D2 580x11 F6 6A 2C 80 19 DE 44
0x00 00 00 00 03 00 3E 000x01 00 B7 4D 55 90 0C 61
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0xDE C0 DE 01 8B 45 FC 890xC7 5D 20 6F 91 03 E4 78
0x13 37 00 4F 9A 2D E1 700x08 B4 5C 22 71 D0 4A 16
0x48 8D 3D 22 01 00 00 E80x91 FF 0A 63 2E 57 B8 04
0x5A 91 C3 0E 44 70 1B 880x02 6F 39 C4 15 80 ED 27
0xFF 15 40 20 60 00 48 890xC3 90 7A 01 4C 28 B1 56
0x0F 1F 44 00 00 55 48 890xE5 C3 18 6D 92 0B 33 A7

Edge Case Audit

This workaround disables static optimization for the route, potentially increasing server load and response time. It is incompatible with `output: 'export'` (static export). If a future Next.js version fixes the underlying bug, this workaround should be removed to restore static optimization. Rollback: remove the `export const dynamic` line from the page.