---
title: "Send a message to a channel (channelId in body)"
method: POST
path: "/api/v1/messages"
tags: ["Messages"]
---

# Send a message to a channel (channelId in body)

`POST /api/v1/messages`

## Request body

- CreateMessageDto
  - `channelId` string, required
  - `text` string
  - `status` 'info' | 'success' | 'warning' | 'error'
  - `review` CreateMessageDtoReview
    - `type` string, required
    - `payload` object
    - `callback` CreateMessageDtoReviewCallback
      - `url` string, uri, required
      - `method` string
      - `headers` object
    - `expiresAt` string, nullable
    - `expiresInSeconds` integer
  - `metadata` object
  - `webhookUrl` string, uri
  - `attachmentIds` string[]
  - `textAttachments` object[]
    - `content` string, required
    - `filename` string
    - `mimeType` string
  - `iterationOf` string

## Response `201`

Message created

- MessageItemResponse
  - `id` string, required
  - `channelId` string, required
  - `senderType` 'agent' | 'user', required
  - `senderId` string, required
  - `text` string
  - `status` 'info' | 'success' | 'warning' | 'error'
  - `review` object — Review object (null if no review)
  - `metadata` object — Arbitrary metadata
  - `createdAt` string, required
  - `attachments` AttachmentResponse[], required
    - `id` string, required
    - `messageId` string, required
    - `pluginType` string, required
    - `filename` string, required
    - `mimeType` string, required
    - `size` number, required
    - `storageKey` string, required
    - `createdAt` string, required

## Other responses

- `401` — Invalid API key
- `403` — Not your agent

## Changes

- **2026-04-06** `3fb7657511b8` — 2 info
  - added the new optional request property `iterationOf`
  - added the new optional request property `textAttachments`
- **2026-04-02** `d05e1eeb4e5c` — 4 info
  - the endpoint scheme security `api-key` was added to the API
  - the endpoint scheme security `bearer` was removed from the API
  - api tag `Messages` added
  - api tag `Agent API` removed

[Change history](https://skmtc.dev/placet-io/apis/placet-api/changes/api/v1/messages/post.md)

---

[API](https://skmtc.dev/placet-io/apis/placet-api.md) · [All operations](https://skmtc.dev/placet-io/apis/placet-api/llms.txt) · [OpenAPI document](https://skmtc-service-production.skmtc.workers.dev/v1/apis/placet-io/placet-api/revisions/3fb7657511b8/schema)