# Error Handling

Foundation APIs use standard HTTP status codes and return structured error responses.

## Error Format

```json
{
  "error": {
    "code": "ENTITY_NOT_FOUND",
    "message": "The requested entity does not exist.",
    "status": 404
  }
}
```

## Common Status Codes

| Code | Meaning |
|------|---------|
| 200 | Success |
| 201 | Created |
| 400 | Bad request — check your input |
| 401 | Unauthorized — invalid or missing authentication |
| 403 | Forbidden — valid auth but insufficient permissions |
| 404 | Not found |
| 429 | Rate limited — slow down |
| 500 | Server error |