---
title: "Parallel route slot without default.tsx (next/parallel-route-default)"
description: "Since Next.js 16 every @slot needs an explicit default.js; the build fails without one."
url: http://localhost:4173/rules/next/parallel-route-default
updated: 2026-11-11
---

# Parallel route slot without default.tsx

> `next/parallel-route-default` is a vetd rule. It flags: Parallel route slot without default.tsx. It runs on every `check`, together with the TypeScript check.

| Fact | Value |
| --- | --- |
| Rule id | `next/parallel-route-default` |
| Severity | error |
| Group | Next.js 16 upgrade |
| Tags | nextjs-16, correctness |

## Why it matters

Since Next.js 16 every @slot needs an explicit default.js; the build fails without one.

## How to fix it

Add default.tsx to the slot (return null, or notFound(), for slots with nothing to show).

## Credit

Based on work by:

- [Next.js team](https://nextjs.org): Next.js 16 requires an explicit default.js for every parallel route slot.

## References

- [default.js](https://nextjs.org/docs/app/api-reference/file-conventions/default), Next.js
- [Parallel Routes](https://nextjs.org/docs/app/api-reference/file-conventions/parallel-routes), Next.js
- [How to upgrade to version 16](https://nextjs.org/docs/app/guides/upgrading/version-16), Next.js

## Get this text from vetd

MCP: call `explain` with `{ "diagnosticId": "next/parallel-route-default" }`. CLI: `npx vetd explain next/parallel-route-default`.

---

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