chat.postMessage

Sends a message to a channel.

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API response

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Calling chat.postMessage

Java

JavaScript

Python

Java

import com.slack.api.bolt.App;
import com.slack.api.bolt.AppConfig;
import com.slack.api.bolt.jetty.SlackAppServer;
import com.slack.api.methods.SlackApiException;

import java.io.IOException;

public class ChatPostMessage {

    public static void main(String[] args) throws Exception {
        var config = new AppConfig();
        config.setSingleTeamBotToken(System.getenv("SLACK_BOT_TOKEN"));
        config.setSigningSecret(System.getenv("SLACK_SIGNING_SECRET"));
        var app = new App(config); // `new App()` does the same

        app.message("hello", (req, ctx) -> {
            var logger = ctx.logger;
            try {
                var event = req.getEvent();
                // Call the chat.postMessage method using the built-in WebClient
                var result = ctx.client().chatPostMessage(r -> r
                    // The token you used to initialize your app is stored in the `context` object
                    .token(ctx.getBotToken())
                    // Payload message should be posted in the channel where original message was heard
                    .channel(event.getChannel())
                    .text("world")
                );
                logger.info("result: {}", result);
            } catch (IOException | SlackApiException e) {
                logger.error("error: {}", e.getMessage(), e);
            }
            return ctx.ack();
        });

        var server = new SlackAppServer(app);
        server.start();
    }
}

JavaScript

Code to initialize Bolt app
// Require the Node Slack SDK package (.com/slackapi/node-slack-sdk)
const { WebClient, LogLevel } = require("@slack/web-api");

// WebClient instantiates a client that can call API methods
// When using Bolt, you can use either `app.client` or the `client` passed to listeners.
const client = new WebClient("xoxb-your-token", {
  // LogLevel can be imported and used to make debugging simpler
  logLevel: LogLevel.DEBUG
});
// ID of the channel you want to send the message to
const channelId = "C12345";

try {
  // Call the chat.postMessage method using the WebClient
  const result = await client.chat.postMessage({
    channel: channelId,
    text: "Hello world"
  });

  console.log(result);
}
catch (error) {
  console.error(error);
}

Python

Code to initialize Bolt app
import logging
import os
# Import WebClient from Python SDK (.com/slackapi/python-slack-sdk)
from slack_sdk import WebClient
from slack_sdk.errors import SlackApiError

# WebClient instantiates a client that can call API methods
# When using Bolt, you can use either `app.client` or the `client` passed to listeners.
client = WebClient(token=os.environ.get("SLACK_BOT_TOKEN"))
logger = logging.getLogger(__name__)
# ID of the channel you want to send the message to
channel_id = "C12345"

try:
    # Call the chat.postMessage method using the WebClient
    result = client.chat_postMessage(
        channel=channel_id, 
        text="Hello world"
    )
    logger.info(result)

except SlackApiError as e:
    logger.error(f"Error posting message: {e}")

chat.postMessage

Arguments

API response