> ## Documentation Index > Fetch the complete documentation index at: https://docs.ando.so/llms.txt > Use this file to discover all available pages before exploring further. # Create a conversation message > Creates a message in a conversation using the authenticated API-key workspace membership as the author. ## OpenAPI ````yaml /api-reference/openapi.json post /conversations/{conversationId}/messages openapi: 3.0.3 info: description: >- Generated from Ando's accepted public API v1 contract metadata. Current routes preserve legacy /api/v1 response envelopes while converging on the public https://api.ando.so/v1 shape. title: Ando Public API version: v1 servers: - description: Canonical public API host. url: https://api.ando.so/v1 security: [] tags: - description: Call detail and transcript routes. name: Calls - description: Clipboard detail routes. name: Clipboards - description: >- Workspace member detail routes. Existing v1 paths keep member compatibility spellings. name: Members - description: Message and conversation message routes. name: Messages - description: Public realtime connection and protocol routes. name: Realtime - description: Search routes. name: Search - description: Task routes. name: Tasks - description: Outbound webhook endpoint and delivery routes. name: Webhooks paths: /conversations/{conversationId}/messages: post: tags: - Messages summary: Create a conversation message description: >- Creates a message in a conversation using the authenticated API-key workspace membership as the author. operationId: createConversationMessage parameters: - description: Conversation identifier. in: path name: conversationId required: true schema: description: Conversation identifier. type: string - description: Required idempotency key for safely retrying this write. in: header name: Idempotency-Key required: true schema: description: Idempotency key. type: string maxLength: 255 requestBody: content: application/json: examples: message: summary: Create a top-level message. value: markdown_content: Can you review this? explicit_context_message_ids: [] image_urls: [] suppressed_link_preview_urls: [] thread_root_id: null schema: $ref: '#/components/schemas/CreateConversationMessageBody' required: true responses: '200': content: application/json: examples: created: summary: Created message. value: success: true data: id: msg_01jzn7e61x3a7v9h2r7t2m3q4p conversation_id: conv_01jzn7e61x3a7v9h2r7t2m3q4p conversation_name: Launch planning authorWorkspaceMembershipId: mem_01jzn7e61x3a7v9h2r7t2m3q4p author_id: mem_01jzn7e61x3a7v9h2r7t2m3q4p author_name: Alex Kim content: Validated the route migration. image_urls: [] reactions: - emoji_text: ':thumbsup:' count: 2 replies_count: 1 created_at: '2026-05-14T08:00:00.000Z' legacy_data: null schema: $ref: '#/components/schemas/CreateConversationMessageResponse' description: Created message. '400': $ref: '#/components/responses/BadRequest' '401': $ref: '#/components/responses/Unauthorized' '403': $ref: '#/components/responses/Forbidden' '404': $ref: '#/components/responses/NotFound' '409': $ref: '#/components/responses/Conflict' '429': $ref: '#/components/responses/RateLimited' '500': $ref: '#/components/responses/InternalError' security: - AndoApiKey: [] - BearerApiKey: [] components: schemas: CreateConversationMessageBody: additionalProperties: false description: >- Create a conversation message. The authenticated API-key workspace member is the author; author_id is accepted only for legacy body compatibility and is ignored. properties: markdown_content: description: Message markdown content. type: string nullable: true explicit_context_message_ids: description: Message identifiers to include as explicit context. items: description: Message identifier. type: string type: array image_urls: description: Image URLs to attach to the message. items: description: Image URL. type: string format: uri type: array suppressed_link_preview_urls: description: URLs whose link previews should be suppressed. items: description: URL. type: string format: uri type: array initiator_id: description: Initiating workspace member identifier. type: string nullable: true thread_root_id: description: Thread root message identifier. type: string nullable: true replied_to_message_id: description: >- Immediate parent message identifier inside an existing thread. For the first reply to a root message, send thread_root_id only; if replied_to_message_id equals thread_root_id, the server normalizes it as the first reply. type: string nullable: true call_root_id: description: Call root identifier. type: string nullable: true optimistic_id: description: Client optimistic identifier. type: string client_request_id: description: >- Legacy body idempotency value. Public v1 clients should use the Idempotency-Key header. type: string nullable: true author_id: description: >- Ignored legacy body author workspace member identifier. Deprecated: the authenticated API-key workspace member is always the author. type: string deprecated: true required: - markdown_content type: object CreateConversationMessageResponse: additionalProperties: false description: >- Create-message response with the standard public data envelope plus legacy compatibility aliases. properties: data: $ref: '#/components/schemas/MessageResult' legacy_data: additionalProperties: true description: >- Legacy extended conversation message. New clients should read the standard data message result. nullable: true type: object success: description: Compatibility command flag. type: boolean required: - success - data type: object MessageResult: additionalProperties: false description: >- Public message result. This intentionally omits reply lineage fields such as thread_root_id and replied_to_message_id; use the thread replies route and its thread_root_id payload field to validate thread grouping. properties: authorWorkspaceMembershipId: description: >- Canonical author workspace membership identifier. Matches legacy author_id during the compatibility window. type: string example: 01jzn7e61x3a7v9h2r7t2m3q4p author_id: description: >- Author workspace member identifier. Deprecated: read authorWorkspaceMembershipId instead. type: string example: 01jzn7e61x3a7v9h2r7t2m3q4p deprecated: true author_name: description: Author workspace member display name. type: string nullable: true content: description: Message markdown content. type: string nullable: true conversation_id: description: Conversation identifier. type: string example: 01jzn7e61x3a7v9h2r7t2m3q4p conversation_name: description: Conversation name. type: string nullable: true created_at: description: Message creation timestamp. type: string example: '2026-05-14T08:00:00.000Z' format: date-time id: description: Message identifier. type: string example: 01jzn7e61x3a7v9h2r7t2m3q4p image_urls: description: Image URLs extracted from the message. items: description: Image URL. type: string format: uri type: array reactions: description: Emoji reaction counts on the message. items: $ref: '#/components/schemas/MessageReactionSummary' type: array replies_count: description: Number of thread replies. type: integer minimum: 0 required: - id - conversation_id - conversation_name - authorWorkspaceMembershipId - author_id - author_name - content - image_urls - reactions - replies_count - created_at type: object LegacyErrorResponse: additionalProperties: false description: Current compatibility error envelope used by legacy /api/v1 routes. properties: error: description: Error message. type: string error_code: description: Optional machine-readable error code. type: string nullable: true missing_scopes: description: Missing scopes. items: description: Scope. type: string type: array required: - error type: object PublicApiErrorResponse: additionalProperties: false description: Target public API error envelope. properties: error: additionalProperties: false description: Error details. properties: code: description: Machine-readable error code. type: string message: description: Human-readable error message. type: string request_id: description: Request identifier. type: string nullable: true required: - code - message type: object required: - error type: object MessageReactionSummary: additionalProperties: false description: Emoji reaction count for a message. properties: count: description: Number of reactions for this emoji. type: integer minimum: 0 emoji_text: description: Emoji text. type: string required: - emoji_text - count type: object responses: BadRequest: content: application/json: schema: $ref: '#/components/schemas/LegacyErrorResponse' description: Bad request. Unauthorized: content: application/json: schema: $ref: '#/components/schemas/LegacyErrorResponse' description: Missing or invalid API key. Forbidden: content: application/json: schema: $ref: '#/components/schemas/LegacyErrorResponse' description: Forbidden. NotFound: content: application/json: schema: $ref: '#/components/schemas/LegacyErrorResponse' description: Not found. Conflict: content: application/json: schema: $ref: '#/components/schemas/LegacyErrorResponse' description: Conflict. RateLimited: content: application/json: schema: $ref: '#/components/schemas/PublicApiErrorResponse' description: Rate limit or quota exceeded. InternalError: content: application/json: schema: $ref: '#/components/schemas/LegacyErrorResponse' description: Internal server error. securitySchemes: AndoApiKey: description: Workspace API key. Current accepted keys use the ando_sk_ prefix. in: header name: x-api-key type: apiKey BearerApiKey: bearerFormat: ando_sk description: Compatibility transport for workspace API keys. scheme: bearer type: http ````