Slack Skill

Slack App Development

Bolt framework + Block Kit for Slack integrations.

Prerequisites

export SLACK_BOT_TOKEN="xoxb-xxx"
export SLACK_SIGNING_SECRET="xxx"
export SLACK_APP_TOKEN="xapp-xxx"  # for socket mode

Quick Start (Bolt)

import { App } from '@slack/bolt';

const app = new App({
  token: process.env.SLACK_BOT_TOKEN,
  signingSecret: process.env.SLACK_SIGNING_SECRET,
  socketMode: true,
  appToken: process.env.SLACK_APP_TOKEN,
});

// Slash command
app.command('/hello', async ({ command, ack, respond }) => {
  await ack();
  await respond(`Hello, ${command.user_name}!`);
});

// Message listener
app.message('hello', async ({ message, say }) => {
  await say(`Hey there <@${message.user}>!`);
});

app.start(3000);

Block Kit

Simple Message

{
  "blocks": [
    {
      "type": "section",
      "text": { "type": "mrkdwn", "text": "*Title*\nDescription" }
    },
    {
      "type": "actions",
      "elements": [
        { "type": "button", "text": { "type": "plain_text", "text": "Click" }, "action_id": "button_click" }
      ]
    }
  ]
}

Webhooks

Incoming Webhook

curl -X POST $WEBHOOK_URL \
  -H "Content-Type: application/json" \
  -d '{"text": "Hello from webhook!"}'

Event Subscriptions

Common events:

• message.channels - Channel messages
• app_mention - Bot mentioned
• reaction_added - Emoji reactions

Best Practices

• Use socket mode for development
• Acknowledge commands within 3 seconds
• Use Block Kit for rich UIs
• Store tokens securely (never in code)