Functions & messages

Automate tasks and handle backend logic without managing servers. Schedule daily jobs, react to events, and extend your app with server-side code.

Perfect for trial expirations, email reminders, data processing, and workflows that need to run on a schedule or in response to events.

Run code on a schedule

// This function runs every day at 9 AM
function handleTrialExpiration() {
  // Find users whose trial expires today
  const users = backend.query('users', {
    trialEndsAt: { $lte: new Date() },
    isPaid: false
  });

  // Send reminder emails
  users.forEach(user => {
    backend.sendEmail(user.email, 'Your trial is ending');
  });
}

Create the schedule in your dashboard: “Daily at 9 AM” or complex patterns like “First Monday of each month at 9 AM.”

What you can automate

• Trial management - Expire trials, send reminders, downgrade accounts
• Email campaigns - Onboarding sequences, newsletters, notifications
• Data cleanup - Delete old records, archive inactive users
• Report generation - Daily summaries, analytics, exports
• Webhooks - Call external APIs on schedule or events
• Data sync - Import/export data from other services

Three ways to run code

1. Scheduled tasks - Run functions at specific times:

// Runs every hour
function cleanupSessions() {
  // Delete expired sessions
}

// Runs every Monday at 8 AM
function sendWeeklyReport() {
  // Generate and email report
}

2. Event triggers - React to system events:

// Runs when a user registers
function onUserRegistered(event) {
  // Send welcome email
  backend.sendEmail(event.user.email, 'Welcome!');
}

// Runs when data is created
function onDocumentCreated(event) {
  // Log activity, notify team, etc.
}

3. Manual execution - Call functions from your frontend:

// From your app
await backend.executeFunction('processData', { id: 123 });

How it works

Write functions in JavaScript and deploy them via the CLI or dashboard. Functions run in a secure, sandboxed environment.

You have access to:

• Database operations (create, query, update, delete)
• Email sending
• HTTP requests to external APIs
• Date/time utilities
• Custom helper functions

Note: Functions run in a custom JavaScript runtime (ES5 compatible), not Node.js. Most standard JavaScript works, but some Node-specific features aren’t available.

Event system

Subscribe to system events or publish your own:

System events:

• user_registered - New user signs up
• user_login - User logs in
• doc_created - Document created in database
• doc_updated - Document updated
• chan_in - Message sent in WebSocket channel

Custom events: You can publish your own events and create functions to handle them:

// Publish from your app
await backend.publishEvent('order_placed', { orderId: 123 });

// Handle in a server function
function onOrderPlaced(event) {
  // Process order, send confirmation, update inventory
}

Real-world example: Chat history

Save chat messages to your database automatically:

// This function triggers when a message is sent in any channel
function onChatMessage(event) {
  backend.create('chat_history', {
    channel: event.channel,
    user: event.user,
    message: event.message,
    timestamp: new Date()
  });
}

Now your real-time chat has permanent history without any frontend code changes.

Deploy and manage

Via CLI:

# Create a new function
backend functions create trial-reminder.js

# Update existing function
backend functions update trial-reminder

# View logs
backend functions logs trial-reminder

Via Dashboard: Create and edit functions directly in your web dashboard. Test them before deploying.

→ View functions documentation for detailed API reference and available helper functions.

Next component is helper functions.