# Error: Parallel route slot '@slot' requires a Suspense boundary or default.tsx

- **ID:** `nextjs/parallel-route-slot-missing-suspense`
- **Domain:** nextjs
- **Category:** build_error
- **Verification:** ai_generated
- **Fix Rate:** 95%

## Root Cause

In Next.js app directory, parallel route slots (e.g., @modal) must be wrapped in a Suspense boundary or have a default.tsx file to handle loading states when the slot is not matched.

## Version Compatibility

| Version | Status | Introduced | Deprecated |
|---------|--------|------------|------------|
| next@14.2.0 | active | — | — |
| next@14.3.0 | active | — | — |
| next@15.0.0 | active | — | — |

## Workarounds

1. **Wrap the parallel route slot in a Suspense boundary in the layout file.** (95% success)
   ```
   Wrap the parallel route slot in a Suspense boundary in the layout file.
   ```
2. **Create a default.tsx file in the slot directory to handle unmatched routes.** (85% success)
   ```
   Create a default.tsx file in the slot directory to handle unmatched routes.
   ```

## Dead Ends

- **** — This may cause layout shifts or missing UI because the slot renders nothing when unmatched, but the error persists if the slot is still not wrapped in Suspense. (50% fail)
- **** — This eliminates the feature, which may not be acceptable for modals or complex layouts. (90% fail)