---
title: "Sends a message to a specified Slack channel."
method: POST
path: "/sendMessage"
---

# Sends a message to a specified Slack channel.

`POST /sendMessage`

This function posts a message to a Slack channel. It's versatile, supporting simple text, rich formatting with Block Kit, threaded replies, and interactive components. It also supports changing the bot icon or name as it appears as needed. On success, it returns details of the sent message.

## Request body

- object
  - `body` object — Body of the sendMessage sls call
    - `arguments` object, required — SlackMessage object containing message details
      - `channel` string, required — Channel ID or name where the message will be sent
      - `text` string, required — Message text content
      - `blocks` object[] — Optional Block Kit blocks for rich message formatting
      - `attachments` object[] — Optional legacy attachments for message formatting
      - `thread_ts` string — Optional timestamp of parent message for threading
      - `reply_broadcast` boolean — Optional flag to broadcast reply in thread

## Response `200`

Successful response

- object
  - `ok` boolean, required — Success indicator
  - `channel` string — Channel ID where the message was sent
  - `ts` string — Timestamp of the sent message
  - `message` object — Message details

## Other responses

- `400` — Bad request
- `401` — Unauthorized - Invalid or missing authentication token
- `429` — Too Many Requests - Rate limit exceeded
- `500` — Internal server error

## Changes

> 17 revisions in range; 1 could not be searched.

- **2025-07-06** `089d0d129999` — 3 breaking, 2 warning, 4 info
  - added the new required request property `body/arguments/channel`
  - added the new required request property `body/arguments/text`
  - the `body/arguments` request property type/format changed from `array`/`` to `object`/``
  - removed the request property `body/auth`
  - …5 more
- **2025-05-29** `d01bc484075b` — 2 info
  - added the non-success response with the status `401`
  - added the non-success response with the status `429`
- **2025-05-27** `8ed465204f85` — 7 warning, 4 info
  - removed the request property `attachments`
  - removed the request property `blocks`
  - removed the request property `channel`
  - removed the request property `reply_broadcast`
  - …7 more
- **2025-05-15** `f4d5f1c6aa29` — 1 info
  - endpoint added
- **2025-05-15** `9da633fac0b3` — 1 breaking
  - api path removed without deprecation

[Change history](https://skmtc.dev/microfox-ai/apis/microfox-slack-web-tiny-api/changes/sendMessage/post.md)

---

[API](https://skmtc.dev/microfox-ai/apis/microfox-slack-web-tiny-api.md) · [All operations](https://skmtc.dev/microfox-ai/apis/microfox-slack-web-tiny-api/llms.txt) · [OpenAPI document](https://skmtc-service-production.skmtc.workers.dev/v1/apis/microfox-ai/microfox-slack-web-tiny-api/revisions/430f57e9b7c5/schema)