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

# Preview dataset restore

> Preview restoring a dataset to an earlier version, such as a dataset snapshot. Returns how many rows a restore would change, without modifying the dataset. Fails if more than 20,000 rows changed since the requested version. Requires read permission on the dataset.



## OpenAPI

````yaml /openapi.yaml post /v1/dataset/{dataset_id}/restore/preview
openapi: 3.1.1
info:
  version: 1.0.0
  title: Braintrust API
  description: >-
    API specification for the backend data server. The API is hosted globally at

    https://api.braintrust.dev or in your own environment.


    You can access the OpenAPI spec for this API at
    https://github.com/braintrustdata/braintrust-openapi.
  license:
    name: Apache 2.0
servers:
  - url: https://api.braintrust.dev
security:
  - bearerAuth: []
  - {}
paths:
  /v1/dataset/{dataset_id}/restore/preview:
    post:
      tags:
        - Datasets
      summary: Preview dataset restore
      description: >-
        Preview restoring a dataset to an earlier version, such as a dataset
        snapshot. Returns how many rows a restore would change, without
        modifying the dataset. Fails if more than 20,000 rows changed since the
        requested version. Requires read permission on the dataset.
      operationId: postDatasetIdRestorePreview
      parameters:
        - $ref: '#/components/parameters/DatasetIdParam'
      requestBody:
        required: true
        content:
          application/json:
            schema:
              $ref: '#/components/schemas/DatasetRestoreRequest'
      responses:
        '200':
          description: Number of rows the restore would change
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/DatasetRestorePreviewResponse'
        '400':
          description: >-
            The request was unacceptable, often due to missing a required
            parameter
          content:
            text/plain:
              schema:
                type: string
            application/json:
              schema: {}
        '401':
          description: No valid API key provided
          content:
            text/plain:
              schema:
                type: string
            application/json:
              schema: {}
        '403':
          description: The API key doesn’t have permissions to perform the request
          content:
            text/plain:
              schema:
                type: string
            application/json:
              schema: {}
        '429':
          description: >-
            Too many requests hit the API too quickly. We recommend an
            exponential backoff of your requests
          headers:
            Retry-After:
              schema:
                type: string
          content:
            text/plain:
              schema:
                type: string
            application/json:
              schema: {}
        '500':
          description: Something went wrong on Braintrust's end. (These are rare.)
          content:
            text/plain:
              schema:
                type: string
            application/json:
              schema: {}
      security:
        - bearerAuth: []
        - {}
components:
  parameters:
    DatasetIdParam:
      schema:
        $ref: '#/components/schemas/DatasetIdParam'
      required: true
      description: Dataset id
      name: dataset_id
      in: path
  schemas:
    DatasetRestoreRequest:
      type: object
      properties:
        version:
          type: string
          description: >-
            The dataset version to restore to, such as the `xact_id` of a
            dataset snapshot
      required:
        - version
    DatasetRestorePreviewResponse:
      type: object
      properties:
        rows_to_restore:
          type: integer
          description: >-
            Number of rows that would be restored to their value at the
            requested version
        rows_to_delete:
          type: integer
          description: >-
            Number of rows created after the requested version that would be
            deleted
      required:
        - rows_to_restore
        - rows_to_delete
    DatasetIdParam:
      type: string
      format: uuid
      description: Dataset id
  securitySchemes:
    bearerAuth:
      type: http
      scheme: bearer
      bearerFormat: API key or JWT
      description: >-
        Most Braintrust endpoints are authenticated by providing your API key as
        a header `Authorization: Bearer [api_key]` to your HTTP request. You can
        create an API key in the Braintrust [organization settings
        page](https://www.braintrustdata.com/app/settings?subroute=api-keys).

````

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