Sending Slack Messages from Your App

In this guide, we'll show you how to send Slack messages directly from your Bolt app. We'll build a user signup flow that automatically posts a notification to your Slack channel whenever a new user registers on your platform. With Bolt and Pica, you can set this up in minutes.

What You'll Build

By the end of this tutorial, you'll have:

• A complete user signup and login system with authentication
• A form collecting user information (name, email, company details, etc.)
• Automatic Slack notifications sent to your team when users sign up
• Beautifully formatted Slack messages with all user details
• Production-ready error handling

Let's get started! 🚀

Step 1: Build the User Signup App

First, let's create a web app with user authentication and a comprehensive signup form.

Prompt Bolt:

Step 2: Create a Slack Connection in Pica

You need to connect your Slack workspace to Pica so your app can send messages to your channels.

How to Connect Slack:

1. Go to the Pica dashboard at: app.picaos.com/connections
2. Click on + Add Connection
3. Select Slack from the list of integrations
4. Authenticate with your Slack workspace
5. Grant the necessary permissions for posting messages
6. Save your connection key - you'll need this later!

Step 3: Choose Your Slack Channel

To send messages to a specific channel, you can use either the channel name or channel ID—both work!

Option 1: Use Channel Name (Easiest)

Simply use the channel name with a # prefix:

• #general
• #team-notifications
• #new-signups

This is the simplest approach and works for all public channels and private channels your Slack app has access to.

Option 2: Use Channel ID

If you prefer to use the Channel ID instead:

1. Open Slack and navigate to the channel you want to use
2. Right-click on the channel name in the sidebar
3. Select "View channel details"
4. Scroll down to the bottom of the details panel
5. Copy the Channel ID (it looks like: C1234567890)

We recommend using the channel name for simplicity, but keep whichever you choose handy—you'll need it in the next step!

Step 4: Generate Your Code with BuildKit

Now we'll use Pica BuildKit to generate the perfect prompt for posting messages to Slack.

Using BuildKit:

1. Go to the BuildKit page at: app.picaos.com/buildkit
2. Type: "Post a message in a slack channel"
3. BuildKit will generate an optimized prompt for you

Or copy the prompt here:

🚀 Next step: Copy the prompt above and paste it into Bolt.new to create your backend logic!

What BuildKit Does:

BuildKit automatically generates a prompt that includes:

• ✅ Proper API authentication setup
• ✅ Slack message posting with rich formatting
• ✅ Support for blocks and attachments
• ✅ User signup notification formatting
• ✅ Error handling best practices
• ✅ Environment variable configuration
• ✅ Integration with your Pica Slack connection

Simply copy the generated prompt and paste it into Bolt.new to create your backend logic!

Step 5: Add Your Secrets to Bolt

Once Bolt generates your application, you'll need to add your API keys as environment variables.

Required Environment Variables:

1. PICA_SECRET_KEY

• Get it from: app.picaos.com/settings/api-keys
• This authenticates your application with Pica

2. PICA_SLACK_CONNECTION_KEY

• Get it from: app.picaos.com/connections
• This is the connection key you saved in Step 2

3. SLACK_CHANNEL_ID

• The channel name or ID from Step 3 (e.g., #general or C1234567890)
• This determines which channel receives the notifications

How to Add Secrets in Bolt:

1. Click on the Settings icon in Bolt
2. Navigate to Secrets
3. Add all three keys with their respective values
4. Save and restart your application

Now your app will automatically send Slack notifications when users sign up! 🎉

Step 6: Try It in Action!

Test your signup flow and watch the magic happen in Slack!

What Happens:

1. A new user fills out the signup form with their information
2. Upon successful registration, your app triggers a Slack notification
3. Your team receives a beautifully formatted message in the designated channel
4. The message includes all user details: name, email, company, role, company size, and how they heard about you

Troubleshooting

Slack messages not sending?

1. Check your environment variables - Make sure all three keys are set correctly in your Bolt secret settings
2. Verify your Slack connection - Go to app.picaos.com/connections and ensure it's active
3. Check channel ID - Ensure you're using the correct Channel ID or name
4. Verify bot permissions - Make sure your Slack app has permission to post in the channel
5. Check Pica logs - View execution logs in your Pica dashboard

Get Help

Questions or need support?

• 📅 Schedule a call with our team
• 📚 Check out the Pica documentation
• 🎥 Watch our video tutorials

Happy building! 🚀