# Frontend API Contracts

Contracts are defined in `src/api/contracts`.

Every service returns:

```json
{
  "data": {},
  "meta": {
    "requestId": "req_..."
  },
  "error": null
}
```

Errors return:

```json
{
  "data": null,
  "meta": {
    "requestId": "req_..."
  },
  "error": {
    "code": "VALIDATION_ERROR",
    "message": "Human-readable message",
    "fields": {}
  }
}
```

Shared DTOs cover pagination, filtering, sorting, bulk operations, jobs, job progress, audit metadata, permission checks, and WebSocket events.