---
title: "Send a message to Slack"
method: POST
path: "/v3/slack/message"
tags: ["v3", "Slack"]
---

# Send a message to Slack

`POST /v3/slack/message`

Send a message to a Slack channel using the team's Slack integration.

This endpoint allows sending messages to Slack channels via Definite's API.
The team must have a configured Slack integration with appropriate permissions.

## Request body

- SlackMessageRequest
  - `integration_id` string, required — The ID of the Slack Integration to use for sending the message
  - `channel_id` string, required — The Slack channel ID where the message should be sent
  - `text` string, required — The text content of the message to send
  - `blocks` object[], nullable — Optional array of Slack Block Kit block objects for advanced message formatting
  - `thread_ts` string, nullable — Optional timestamp to post message as a reply in an existing thread

## Response `200`

Message sent successfully

- SlackMessageResponse
  - `ok` boolean, required — Whether the message was sent successfully
  - `channelId` string, required — The Slack channel ID where the message was posted
  - `ts` string, required — The Slack timestamp ID of the new message
  - `threadTs` string, nullable — Thread timestamp if the message was posted in a thread

## Other responses

- `400` — Bad request - invalid parameters or Slack integration not found
- `401` — Unauthorized
- `403` — Forbidden
- `422` — Validation Error
- `502` — Slack API error

---

[API](https://skmtc.dev/definite/apis/defapi.md) · [All operations](https://skmtc.dev/definite/apis/defapi/llms.txt) · [OpenAPI document](https://skmtc-service-production.skmtc.workers.dev/v1/apis/definite/defapi/revisions/3943d8deb3be/schema)