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

# Metadata

Metadata is useful for storing additional, structured information on an object that is only visible to your application.  For example, you can store your patient ID from your system on an Elation patient object.  Metadata is not used by Elation and won't be shown in the EMR.  At the moment, the `patient`, `appointment`,  `bill`, `practice`, and `physician` object supports the `metadata` field and we plan to add metadata support to other objects in the future.  Any fields inside `metadata` can be updated and set to null.

You cannot search objects by `metadata.object_id` or any sub-fields within the `metadata` object because they are currently opaque to Elation.

## Metadata JSON

```json theme={null}
{
  // other fields
  "metadata": {
    "object_id": "opaque id of your choice", // max 100 chars
    "data": {                                // max 1000 chars
    	// any structured (valid json) data
    },
    "object_web_link": "https://test.website/webhook_receiver" // max 200 chars
  }
}
```

## Sample usage (storing your own patient ID in the patient object)

```json theme={null}
{
  "first_name": "Sample",
  "last_name": "Patient",
  // other patient fields
  "metadata": {
    "object_id": "unique_patient_id_in_your_system",
    "data": {
      "alias": "alias in your system",
      "last_sync": "2017-01-03T00:00:00Z",
      "other_ids": [
        "sdf23423", "4394611", "khjh23cxlz"
      ]
    },
    "object_web_link": "https://test.website/webhook_receiver"
  }
}
```