> ## Documentation Index > Fetch the complete documentation index at: https://dify-6c0370d8-fix-template-upload-size-guidance.mintlify.site/llms.txt > Use this file to discover all available pages before exploring further. # Update Document Metadata in Batch > Update metadata values for multiple documents in a single request. ## OpenAPI ````yaml /en/api-reference/openapi_service.json post /datasets/{dataset_id}/documents/metadata openapi: 3.0.1 info: description: >- REST API for Dify applications and knowledge bases. Application endpoints authenticate with an app API key; knowledge endpoints authenticate with a dataset API key. title: Dify Service API version: 1.0.0 servers: - description: >- Base URL of the Dify Service API. For self-hosted deployments, replace it with your own API base URL. url: https://{api_base_url} variables: api_base_url: default: api.dify.ai/v1 description: Host and path of the API base URL, without the `https://` prefix. security: - ApiKeyAuth: [] tags: - description: Operations related to chat messages and interactions. name: Chat Messages - description: File upload and preview operations. name: Files - description: Operations related to end user information. name: End Users - description: User feedback operations. name: Feedback - description: Operations related to managing conversations. name: Conversations - description: Text-to-Speech and Speech-to-Text operations. name: Audio - description: Operations to retrieve application settings and information. name: Applications - description: Operations related to managing annotations for direct replies. name: Annotations - description: Endpoints for resuming paused workflows that require human input. name: Human Input - description: Operations for executing and managing workflows. name: Workflow Runs - description: Operations related to text generation and completion. name: Completion Messages - description: >- Operations for managing knowledge bases, including creation, configuration, and retrieval. name: Knowledge Bases - description: >- Operations for creating, updating, and managing documents within a knowledge base. name: Documents - description: Operations for managing document chunks and child chunks. name: Chunks - description: >- Operations for managing knowledge base metadata fields and document metadata values. name: Metadata - description: Operations for managing knowledge base tags and tag bindings. name: Tags - description: Operations for retrieving available models. name: Models - description: >- Operations for managing and running knowledge pipelines, including datasource plugins and pipeline execution. name: Knowledge Pipeline paths: /datasets/{dataset_id}/documents/metadata: post: tags: - Metadata summary: Update Document Metadata in Batch description: Update metadata values for multiple documents in a single request. operationId: batchUpdateDocumentMetadata parameters: - description: >- Knowledge base ID. See [List Knowledge Bases](/en/api-reference/knowledge-bases/list-knowledge-bases). in: path name: dataset_id required: true schema: format: uuid type: string requestBody: content: application/json: schema: properties: operation_data: description: Document metadata update operations, one entry per document. items: properties: document_id: description: >- ID of the document to update. See [List Documents](/en/api-reference/documents/list-documents). type: string metadata_list: description: Metadata fields to set on the document. items: properties: id: description: >- Metadata field ID. See [List Metadata Fields](/en/api-reference/metadata/list-metadata-fields). type: string name: description: Metadata field name. type: string value: description: >- Metadata value. Can be a string, number, or `null`. required: - id - name type: object type: array partial_update: default: false description: >- Whether to partially update metadata, keeping existing values for unspecified fields. type: boolean required: - document_id - metadata_list type: object type: array required: - operation_data type: object required: true responses: '200': content: application/json: examples: success: summary: Response Example value: result: success schema: properties: result: description: Operation result. type: string type: object description: Document metadata updated successfully. '400': content: application/json: examples: invalid_param: summary: invalid_param value: code: invalid_param message: >- Another document metadata operation is running, please wait a moment. status: 400 description: >- `invalid_param` : Another metadata operation is already running for a document in this request. '403': content: application/json: examples: forbidden_1: summary: forbidden (api access) value: code: forbidden message: Dataset api access is not enabled. status: 403 forbidden_2: summary: forbidden (rate limit) value: code: forbidden message: >- Sorry, you have reached the knowledge base request rate limit of your subscription. status: 403 description: >- - `forbidden` : Dataset api access is not enabled. - `forbidden` : Sorry, you have reached the knowledge base request rate limit of your subscription. '404': content: application/json: examples: not_found_1: summary: not_found (knowledge base) value: code: not_found message: Dataset not found. status: 404 not_found_2: summary: not_found (document) value: code: not_found message: Document not found. status: 404 not_found_3: summary: not_found (metadata) value: code: not_found message: Metadata not found. status: 404 description: >- - `not_found` : Knowledge base not found. - `not_found` : A document referenced in `operation_data` does not exist in this knowledge base. - `not_found` : A metadata field referenced in `metadata_list` does not exist in this knowledge base. components: securitySchemes: ApiKeyAuth: bearerFormat: API_KEY description: >- Every request authenticates with an API key: `Authorization: Bearer {API_KEY}`. App endpoints take an app API key; knowledge endpoints take a knowledge base API key ([Get Started](/en/api-reference/guides/get-started)). Keep keys server-side; never embed them in client code. Requests with a missing or invalid key fail with HTTP `401` (`unauthorized`). scheme: bearer type: http ````