Slack Bot Builder

Patterns

Bolt App Foundation Pattern

The Bolt framework is Slack's recommended approach for building apps. It handles authentication, event routing, request verification, and HTTP request processing so you can focus on app logic.

Key benefits:

•Event handling in a few lines of code
•Security checks and payload validation built-in
•Organized, consistent patterns
•Works for experiments and production

Available in: Python, JavaScript (Node.js), Java

When to use: ['Starting any new Slack app', 'Migrating from legacy Slack APIs', 'Building production Slack integrations']

python

# Python Bolt App
from slack_bolt import App
from slack_bolt.adapter.socket_mode import SocketModeHandler
import os

# Initialize with tokens from environment
app = App(
    token=os.environ["SLACK_BOT_TOKEN"],
    signing_secret=os.environ["SLACK_SIGNING_SECRET"]
)

# Handle messages containing "hello"
@app.message("hello")
def handle_hello(message, say):
    """Respond to messages containing 'hello'."""
    user = message["user"]
    say(f"Hey there <@{user}>!")

# Handle slash command
@app.command("/ticket")
def handle_ticket_command(ack, body, client):
    """Handle /ticket slash command."""
    # Acknowledge immediately (within 3 seconds)
    ack()

    # Open a modal for ticket creation
    client.views_open(
        trigger_id=body["trigger_id"],
        view={
            "type": "modal",
            "callback_id": "ticket_modal",
            "title": {"type": "plain_text", "text": "Create Ticket"},
            "submit": {"type": "plain_text", "text": "Submit"},
            "blocks": [
                {
                    "type": "input",
                    "block_id": "title_block",
                    "element": {
                        "type": "plain_text_input",
                        "action_id": "title_input"
                    },
                    "label": {"type": "plain_text", "text": "Title"}
                },
                {
                    "type": "input",
                    "block_id": "desc_block",
                    "element": {
                        "type": "plain_text_input",
                        "multiline": True,
                        "action_id": "desc_input"
                    },
                    "label": {"type": "plain_text", "text": "Description"}
                },
                {
                    "type": "input",
                    "block_id": "priority_block",
                    "element": {
                        "type": "static_select",
                        "action_id": "priority_select",

Block Kit UI Pattern

Block Kit is Slack's UI framework for building rich, interactive messages. Compose messages using blocks (sections, actions, inputs) and elements (buttons, menus, text inputs).

Limits:

•Up to 50 blocks per message
•Up to 100 blocks in modals/Home tabs
•Block text limited to 3000 characters

Use Block Kit Builder to prototype: https://app.slack.com/block-kit-builder

When to use: ['Building rich message layouts', 'Adding interactive components to messages', 'Creating forms in modals', 'Building Home tab experiences']

python

from slack_bolt import App
import os

app = App(token=os.environ["SLACK_BOT_TOKEN"])

def build_notification_blocks(incident: dict) -> list:
    """Build Block Kit blocks for incident notification."""
    severity_emoji = {
        "critical": ":red_circle:",
        "high": ":large_orange_circle:",
        "medium": ":large_yellow_circle:",
        "low": ":white_circle:"
    }

    return [
        # Header
        {
            "type": "header",
            "text": {
                "type": "plain_text",
                "text": f"{severity_emoji.get(incident['severity'], '')} Incident Alert"
            }
        },
        # Details section
        {
            "type": "section",
            "fields": [
                {
                    "type": "mrkdwn",
                    "text": f"*Incident:*\n{incident['title']}"
                },
                {
                    "type": "mrkdwn",
                    "text": f"*Severity:*\n{incident['severity'].upper()}"
                },
                {
                    "type": "mrkdwn",
                    "text": f"*Service:*\n{incident['service']}"
                },
                {
                    "type": "mrkdwn",
                    "text": f"*Reported:*\n<!date^{incident['timestamp']}^{date_short} {time}|{incident['timestamp']}>"
                }
            ]
        },
        # Description
        {
            "type": "section",
            "text": {
                "type": "mrkdwn",
                "text": f"*Description:*\n{incident['description'][:2000]}"
            }
        },
        # Divider
        {"type": "divider"},
        # Action buttons
        {
            "type": "actions",
            "block_id": f"incident_actions_{incident['id']}",
            "elements": [