> ## Documentation Index
> Fetch the complete documentation index at: https://docs.elementary-data.com/llms.txt
> Use this file to discover all available pages before exploring further.

# JSON schema

`elementary.json_schema`

Allows validating that a string column matches a given JSON schema. The test expects a JSON schema as input,
defined according to the [JSON schema standard](https://json-schema.org/), defined in YAML format (see an example below).

This test along with the relevant JSON schema can be auto-generated (see details below).

<Info>
  This test relies on our [Python tests capability](/data-tests/python-tests), and is currently only supported for
  Snowflake and BigQuery data warehouses.
</Info>

### Auto-generate JSON schema tests

Elementary provides the `generate_json_schema_test` macro in order to auto-generate the JSON schema for a given
column using existing data.

Example usage:

```shell theme={null}
dbt run-operation elementary.generate_json_schema_test --args '{"node_name": "login_events", "column_name": "raw_event_data"}'
```

Will print:

```shell theme={null}
Please add the following test to your model configuration:
----------------------------------------------------------

columns:
  - name: raw_event_data
    data_tests:
      - elementary.json_schema:
          arguments:
            type: object
            properties:
              event_id:
                type: integer
              event_name:
                type: string
              event_args:
                type: array
                items:
                  type: string
            required:
              - event_id
              - event_name
```

*Note: The `generate_json_schema_test` macro relies on a 3rd-party python library called `genson`. If you are using
BigQuery, you will need to pre-install this library in your Dataproc cluster (See [dbt's documentation on Python models](https://docs.getdbt.com/docs/building-a-dbt-project/building-models/python-models#specific-data-platforms)
for more details)*

<RequestExample>
  ```yml Models theme={null}
  version: 2

  models:
    - name: < model name >
      columns:
        - name: < column name >
          data_tests:
            - elementary.json_schema: 
                arguments:
                  <json schema parameters>
  ```

  ```yml Models example theme={null}
  version: 2

  models:
    - name: login_events
      columns:
        - name: raw_event_data
          data_tests:
            - elementary.json_schema:
                arguments:
                  type: object
                  properties:
                    event_id:
                      type: integer
                    event_name:
                      type: string
                    event_args:
                      type: array
                      items:
                        type: string
                  required:
                    - event_id
                    - event_name
  ```
</RequestExample>