> ## 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 Conversation Variable > **Available for**: Chatflow, Chatbot, Legacy Agent apps. Updates a conversation variable's value. The new value must match the variable's existing type. ## OpenAPI ````yaml /en/api-reference/openapi_service.json put /conversations/{conversation_id}/variables/{variable_id} 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: /conversations/{conversation_id}/variables/{variable_id}: put: tags: - Conversations summary: Update Conversation Variable description: >- **Available for**: Chatflow, Chatbot, Legacy Agent apps. Updates a conversation variable's value. The new value must match the variable's existing type. operationId: updateChatConversationVariable parameters: - description: >- ID of the conversation that owns the variable. Get conversation IDs from [List Conversations](/en/api-reference/conversations/list-conversations). in: path name: conversation_id required: true schema: format: uuid type: string - description: >- ID of the variable to update. Get variable IDs from [List Conversation Variables](/en/api-reference/conversations/list-conversation-variables). in: path name: variable_id required: true schema: format: uuid type: string requestBody: content: application/json: examples: updateStringVariable: summary: Request Example value: user: abc-123 value: new value schema: $ref: '#/components/schemas/ConversationVariableUpdateRequest' required: true responses: '200': content: application/json: examples: updatedVariable: summary: Response Example value: created_at: 1705407629 description: User preference setting id: a1b2c3d4-5678-90ab-cdef-1234567890ab name: user_preference updated_at: 1705411229 value: new value value_type: string schema: $ref: '#/components/schemas/ConversationVariableItem' description: Variable updated successfully. '400': content: application/json: examples: not_chat_app: summary: not_chat_app value: code: not_chat_app message: Please check if your app mode matches the right API route. status: 400 type_mismatch: summary: bad_request value: code: bad_request message: >- Type mismatch: variable 'user_preference' expects string, but got number type status: 400 description: |- - `not_chat_app` : App mode does not match the API route. - `bad_request` : Variable value type mismatch. '404': content: application/json: examples: conversation_not_exists: summary: not_found value: code: not_found message: Conversation Not Exists. status: 404 variable_not_exists: summary: not_found value: code: not_found message: Conversation Variable Not Exists. status: 404 description: |- - `not_found` : Conversation does not exist. - `not_found` : Conversation variable does not exist. components: schemas: ConversationVariableUpdateRequest: description: Request body for updating a conversation variable. properties: user: description: >- End-user identifier, defined by your app and unique within it. See [End User Identity](/en/api-reference/guides/end-user-identity). type: string value: description: >- The new value for the variable. Must match the variable's expected type. required: - value type: object ConversationVariableItem: properties: created_at: description: Creation timestamp. format: int64 type: integer description: description: Variable description. type: string id: description: Variable ID. format: uuid type: string name: description: Variable name. type: string updated_at: description: Last update timestamp. format: int64 type: integer value: description: Variable value (can be a JSON string for complex types). type: string value_type: description: >- Variable value type. Possible values: `string`, `number`, `object`, `secret`, `file`, `boolean`, `array[any]`, `array[string]`, `array[number]`, `array[object]`, `array[file]`, `array[boolean]`. type: string type: object 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 ````