Slack Bot Builder

Build Slack apps using the Bolt framework across Python, JavaScript, and Java. Covers Block Kit for rich UIs, interactive components, slash commands, event handling, OAuth installation flows, and Workflow Builder integration. Focus on best practices for production-ready Slack apps.

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 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",
                    "options": [
                        {"text": {"type": "plain_text", "text": "Low"}, "value": "low"},
                        {"text": {"type": "plain_text", "text": "Medium"}, "value": "medium"},
                        {"text": {"type": "plain_text", "text": "High"}, "value": "high"}
                    ]
                },
                "label": {"type": "plain_text", "text": "Priority"}
            }
        ]
    }
)

Handle modal submission

@app.view("ticket_modal") def handle_ticket_submission(ack, body, client, view): """Handle ticket modal submission.""" ack()

# Extract values from the view
values = view["state"]["values"]
title = values["title_block"]["title_input"]["value"]
desc = values["desc_block"]["desc_input"]["value"]
priority = values["priority_block"]["priority_select"]["selected_option"]["value"]
user_id = body["user"]["id"]

# Create ticket in your system
ticket_id = create_ticket(title, desc, priority, user_id)

# Notify user
client.chat_postMessage(
    channel=user_id,
    text=f"Ticket #{ticket_id} created: {title}"
)

Handle button clicks

@app.action("approve_button") def handle_approval(ack, body, client): """Handle approval button click.""" ack()

# Get context from the action
user = body["user"]["id"]
action_value = body["actions"][0]["value"]

# Update the message to remove interactive elements
# (Best practice: prevent double-clicks)
client.chat_update(
    channel=body["channel"]["id"],
    ts=body["message"]["ts"],
    text=f"Approved by <@{user}>",
    blocks=[]  # Remove interactive blocks
)

Listen for app_home_opened events

@app.event("app_home_opened") def update_home_tab(client, event): """Update the Home tab when user opens it.""" client.views_publish( user_id=event["user"], view={ "type": "home", "blocks": [ { "type": "section", "text": {