---
title: "Send chat message"
method: POST
path: "/social-post-ideas/send-chat-message"
tags: ["Social Post Ideas"]
---

# Send chat message

`POST /social-post-ideas/send-chat-message`

## Request

- Base URL: `https://api.synup.com/api/v4`
- URL: `https://api.synup.com/api/v4/social-post-ideas/send-chat-message`
- Auth: none required
- TypeScript: <https://skmtc.dev/synup/apis/synup-api/docs/social-post-ideas/send-chat-message/post.ts> (a function with typed inputs; its response is checked against the schema)

Sends a message to an AI post-idea chat session and returns the assistant's reply. The response may include a generated post idea card (`postCard`), follow-up action chips, and a series plan when relevant. Optionally attach `referenceImageUrls` for image-grounded generation.

## Headers

- `Synup-Version` string, required
- `Authorization` string, required

## Request body

- SendChatMessageRequest
  - `sessionId` string, required
  - `message` string, required
  - `referenceImageUrls` string[]

## Response `200`

Successful response

- object
  - `data` object
    - `sendChatMessage` ChatMessageResponseV2
      - `success` boolean
      - `message` ChatMessage
        - `id` string
        - `role` string
        - `content` string
        - `messageType` string
        - `metadata` object
        - `sequence` integer
        - `createdAt` string
      - `postCard` object: Generated post idea card (see Post idea for the full shape), when produced.
      - `seriesPlan` object: Content-series plan, when produced.
      - `actionChips` ActionChipV2[]
        - `label` string
        - `emoji` string
        - `action` string
      - `error` Error
        - `message` string
        - `code` string
        - `contextInfo` object[]
          - `key` string
          - `value` string

## Other responses

- `401`: Unauthorized - Invalid or missing API key

---

[API](https://skmtc.dev/synup/apis/synup-api.md) - [All operations](https://skmtc.dev/synup/apis/synup-api/llms.txt) - [OpenAPI document](https://skmtc.dev/synup/apis/synup-api/revisions/67de2d51c22e?raw)