> For the complete documentation index, see [llms.txt](https://docs.pyck.cloud/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.pyck.cloud/graphql-api/interfaces/withcustomdata.md).

# WithCustomData

Interface for entities with custom JSON data fields

Audience: Programmer

The `WithCustomData` interface is implemented by entities that support storing custom attributes in a JSON data field. This enables flexible schema extension without database migrations.

## Fields

| Field  | Type  | Description                      |
| ------ | ----- | -------------------------------- |
| `data` | `Map` | Custom attributes stored as JSON |

## Implementing Types

* InventoryItem
* Customer
* Supplier
* PickingOrder
* PickingOrderItem
* ReceivingInbound
* ReceivingInboundItem
* Repository
* RepositoryMovement
* InventoryCollection
* InventoryItemSet
* Transaction
* Workflow
* WorkflowSignal

## Usage

```graphql
query {
  inventoryItems(
    where: {
      Data: ["color", "red"]
      DataHasKey: "size"
    }
  ) {
    edges {
      node {
        id
        data  # Map field from WithCustomData
      }
    }
  }
}
```

## Querying Data Fields

Use these filters to query JSON data:

* `Data` - Match exact value at path
* `DataHasKey` - Check if key exists
* `DataIn` - Value is in list
* `DataContains` - String contains substring

See [Advanced JSON Field Queries](https://github.com/pyck-ai/docs/blob/main/graphql/advanced/json-field-queries.md) for detailed examples.

## Best Practices

1. Define a schema for your custom data
2. Document expected fields
3. Validate data structure on write
4. Use consistent naming conventions
5. Consider performance for deep queries

## See Also

* [Map Scalar](/graphql-api/scalars/map.md) - The Map type used for data
* [Advanced JSON Queries](https://github.com/pyck-ai/docs/blob/main/graphql/advanced/json-field-queries.md) - Query techniques


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