---
title: "Send a message to a Slack channel."
method: POST
path: "/messageChannel"
tags: ["message", "channel"]
---

# Send a message to a Slack channel.

`POST /messageChannel`

Sends a text message to a Slack channel. Returns details about the sent message including its timestamp and channel.

## Request body

- object
  - `body` object — Body of the messageChannel sls call
    - `arguments` object, required
      - `channelId` string, required — The ID of the channel to send the message to. Channel IDs start with 'C'.
      - `text` string, required — The text of the message.
      - `username` string — Optional custom username for the message.
      - `icon_url` string — Optional URL to an image to use as the icon for the message.

## Response `200`

Successful response

- object
  - `ok` boolean, required — true if the request was successful.
  - `channel` string, required — The ID of the channel where the message was posted.
  - `ts` string, required — The timestamp of the message.
  - `message` object, required — An object containing the details of the sent message.

## Other responses

- `400` — Bad Request - The request was invalid or cannot be served.
- `500` — Internal Server Error - The server encountered an unexpected condition that prevented it from fulfilling the request.

## Changes

- **2025-07-23** `a34e4f697384` — 2 info
  - added the new optional request property `body/arguments/icon_url`
  - added the new optional request property `body/arguments/username`
- **2025-07-15** `c28a413c6b00` — 4 breaking, 7 warning, 3 info
  - the response property `error` became optional for the status `400`
  - the response property `error` became optional for the status `500`
  - removed the required property `ok` from the response with the `400` status
  - removed the required property `ok` from the response with the `500` status
  - …10 more
- **2025-07-10** `b883cbfe46f6` — 1 info
  - endpoint added
- **2025-06-20** `37c50ff8be3a` — 1 breaking
  - api path removed without deprecation

[Change history](https://skmtc.dev/microfox-ai/apis/slack-d/changes/messageChannel/post.md)

---

[API](https://skmtc.dev/microfox-ai/apis/slack-d.md) · [All operations](https://skmtc.dev/microfox-ai/apis/slack-d/llms.txt) · [OpenAPI document](https://skmtc-service-production.skmtc.workers.dev/v1/apis/microfox-ai/slack-d/revisions/cd0edf0c2cdf/schema)