# Create dataset items from JSON file

**POST** `/v1/private/datasets/items/from-json`

Create dataset items from an uploaded JSON or JSONL file. JSON files must contain a top-level array of objects.
JSONL files contain one JSON object per non-blank line; multi-line JSON objects are not supported.
Reserved keys (id, source, description, tags, evaluators, execution_policy) are extracted into the
corresponding DatasetItem fields; all remaining keys form the item's data map and preserve their JSON types.
To link dataset items to specific traces or spans use the dedicated /items/from-traces or /items/from-spans endpoints.
Processing happens asynchronously in batches. With dataset versioning enabled, a supplied id acts as an upsert key.

Base URL: `https://www.comet.com/opik/api`

Tags: `Datasets`

## Authorization

This operation requires no authorization.

## Request body

Optional. Media type: `multipart/form-data`

### Example request body

```json
{
  "dataset_id": "00000000-0000-0000-0000-000000000000",
  "file": {},
  "format": "json"
}
```

## Responses

| Status | Description | Media type |
| --- | --- | --- |
| `202` | Accepted - JSON processing started | — |
| `400` | Bad Request | `application/json` |

### Example response: 400 — Bad Request

```json
{
  "code": 0,
  "details": "string",
  "message": "string"
}
```

## Related pages

- [Activate a pairing session](./activatepairingsession.md)
- [Add blueprint to existing config](./updateagentconfig.md)
- [Add items to annotation queue](./additemstoannotationqueue.md)
- [Add span comment](./addspancomment.md)
- [Add span feedback score](./addspanfeedbackscore.md)
- [Add thread comment](./addthreadcomment.md)
- [Add trace comment](./addtracecomment.md)
- [Add trace feedback score](./addtracefeedbackscore.md)
- [Agent Configs](./tags/agent-configs.md)
- [Agent Insights](./tags/agent-insights.md)

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