> ## Documentation Index > Fetch the complete documentation index at: https://docs.social-api.ai/llms.txt > Use this file to discover all available pages before exploring further. # Send a message in a conversation > Sends an outgoing DM via the connected platform account and records it in the conversation. ## OpenAPI ````yaml /api-reference/openapi.json post /inbox/conversations/{id}/messages openapi: 3.0.0 info: description: >- Unified social media inbox API. Read and respond to comments, DMs, reviews, and mentions across Instagram, Facebook, Threads, Google Business Profile, TikTok, LinkedIn, and YouTube through a single REST API. X/Twitter and Trustpilot coming soon. title: SocialAPI.AI contact: name: SocialAPI.AI Support email: support@social-api.ai license: name: MIT version: '1.0' servers: - url: https://api.social-api.ai/v1 security: [] paths: /inbox/conversations/{id}/messages: post: tags: - Inbox summary: Send a message in a conversation description: >- Sends an outgoing DM via the connected platform account and records it in the conversation. parameters: - description: Conversation ID name: id in: path required: true schema: type: string requestBody: content: application/json: schema: $ref: '#/components/schemas/api_endpoints.SendMessageRequest' description: Message payload required: true responses: '200': description: Message sent with ID content: application/json: schema: $ref: '#/components/schemas/api_endpoints.SendMessageResponse' '400': description: >- Invalid request body, missing required fields, or messaging window closed (Instagram code platform.instagram.window_closed: the recipient must message you first to reopen the 24-hour window) content: application/json: schema: $ref: '#/components/schemas/api_endpoints.ErrorResponse' '401': description: Invalid or missing API key content: application/json: schema: $ref: '#/components/schemas/api_endpoints.ErrorResponse' '403': description: >- Platform rejected the request (e.g. platform.instagram.permission_denied), or account requires reconnection (account.reconnection_required) content: application/json: schema: $ref: '#/components/schemas/api_endpoints.ErrorResponse' '404': description: Conversation or account not found content: application/json: schema: $ref: '#/components/schemas/api_endpoints.ErrorResponse' '429': description: Platform rate limit exceeded content: application/json: schema: $ref: '#/components/schemas/api_endpoints.ErrorResponse' '501': description: Platform does not support sending DMs content: application/json: schema: $ref: '#/components/schemas/api_endpoints.ErrorResponse' security: - BearerAuth: [] components: schemas: api_endpoints.SendMessageRequest: type: object required: - account_id properties: account_id: type: string example: acc_abc123 attachment_url: description: >- AttachmentURL is a single-attachment shorthand. Ignored when attachments is non-empty; its type is inferred from the URL extension. Deprecated: use Attachments instead, which supersedes it and supports one or many items. type: string example: https://cdn.example.com/photo.jpg attachments: description: >- Attachments sends one or more media items, each as its own message bubble. type: array items: $ref: '#/components/schemas/api_endpoints.DMAttachmentInput' buttons: description: >- Buttons renders a button template (1-3 buttons); uses text as the bubble body. type: array items: $ref: '#/components/schemas/api_endpoints.MessageButton' cards: description: Cards renders a generic/carousel template (up to 10 cards). type: array items: $ref: '#/components/schemas/api_endpoints.MessageCard' message_tag: description: >- MessageTag attaches a Meta message tag so the DM can be sent outside the standard 24-hour window. Instagram/Facebook only. Instagram accepts only HUMAN_AGENT; Facebook also accepts ACCOUNT_UPDATE, CONFIRMED_EVENT_UPDATE, CUSTOMER_FEEDBACK, POST_PURCHASE_UPDATE. Requires Meta "Human Agent" advanced access for HUMAN_AGENT. Ignored by non-Meta platforms. For beta testers replying on Facebook Messenger, HUMAN_AGENT is applied automatically when this field is omitted. type: string example: HUMAN_AGENT quick_replies: description: >- QuickReplies renders up to 13 tappable chips above the keyboard; requires text. type: array items: $ref: '#/components/schemas/api_endpoints.MessageQuickReply' reply_to_message_id: description: >- ReplyToMessageID makes the first sent bubble a reply to a specific prior message (Meta message.reply_to.mid). Instagram/Facebook only. type: string example: m_1234567890 text: type: string example: Thanks for your message! api_endpoints.SendMessageResponse: type: object properties: message_id: description: >- MessageID is the first sent message's ID; for a multi-attachment send it is only the first of several IDs. Deprecated: use MessageIDs instead. type: string example: m_1234567890 message_ids: description: MessageIDs holds every sent message's ID, in send order. type: array items: type: string example: - m_1234567890 success: type: boolean example: true api_endpoints.ErrorResponse: type: object properties: error: $ref: '#/components/schemas/api_endpoints.ErrorBody' api_endpoints.DMAttachmentInput: type: object properties: source: description: >- Source is the attachment reference; its meaning is given by source_type. type: string example: 550e8400-e29b-41d4-a716-446655440000 source_type: description: |- SourceType selects how Source is interpreted: - "url": Source is a publicly reachable media URL the platform fetches directly. - "media_id": Source is a file id in your SocialAPI media library (GET /v1/media); the server resolves it to a temporary URL before sending. - "platform_attachment_id": Source is an id of media already uploaded to the target platform (for example a Meta attachment_id) to reuse without re-upload. type: string enum: - url - media_id - platform_attachment_id example: media_id type: description: >- Type is the media kind. Optional for url and media_id sources (inferred from the file), required for platform_attachment_id (the platform exposes no URL to infer from). type: string enum: - image - video - audio - file example: image api_endpoints.MessageButton: type: object properties: payload: type: string example: VIEW_ORDER title: type: string example: View order type: type: string enum: - url - postback example: url url: type: string example: https://shop.example.com/orders/1 api_endpoints.MessageCard: type: object properties: buttons: type: array items: $ref: '#/components/schemas/api_endpoints.MessageButton' image_url: type: string example: https://cdn.example.com/p.jpg subtitle: type: string example: Short description title: type: string example: Product name api_endpoints.MessageQuickReply: type: object properties: payload: type: string example: TRACK_ORDER title: type: string example: Track my order api_endpoints.ErrorBody: type: object properties: code: type: string example: resource.not_found message: type: string example: Account not found meta: type: object additionalProperties: {} securitySchemes: BearerAuth: description: >- Prefix your API key with "Bearer ". Example: `Authorization: Bearer sapi_key_...` type: apiKey name: Authorization in: header ````