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

# Fetch UI Map Diff

> Get changes to the accessibility tree since last snapshot

## Description

Returns the diff of the accessibility tree compared to the previous snapshot. Only nodes that have been added, removed, or changed are included. Useful for detecting page changes after an action without fetching the full tree.

## Authentication

Open-source deployments do not require authentication by default. If your server config enables `X-API-Key`, include that header with the request.

## Path Parameters

<ParamField path="id" type="string" required>
  The browser ID returned from Create Session.
</ParamField>

## Response

Returns an array of changed UI node objects. Same structure as [Fetch UI Map](/api-reference/endpoints/ui-map/get).

<ResponseField name="[].id" type="integer">
  Unique node ID within the current page.
</ResponseField>

<ResponseField name="[].parent_id" type="integer">
  ID of the parent node.
</ResponseField>

<ResponseField name="[].name" type="string">
  Accessible name of the element.
</ResponseField>

<ResponseField name="[].role" type="string">
  ARIA role of the element.
</ResponseField>

<ResponseField name="[].properties" type="object">
  Additional accessibility properties.
</ResponseField>

## Example

```bash theme={null}
curl http://localhost:8080/browsers/exc-b9534e98-c3ce-4d1b-9671-b563ac66adc3/ui-map-diff/
```

<ResponseExample>
  ```json 200 theme={null}
  [
    {
      "id": 42,
      "parent_id": 2,
      "name": "Search Results",
      "role": "\"list\"",
      "properties": {
        "Focusable": false
      }
    }
  ]
  ```
</ResponseExample>