Skip to main content

​
Queue System

Run background tasks after your function returns to the user. Perfect for sending emails, processing images, updating analytics, or calling external APIs without making users wait.

​
Overview

Key features:
  • Non-blocking — returns immediately to the user
  • Fire-and-forget — no waiting for completion
  • Works in both HTTP and WebSocket functions
  • Not persisted — lost on server restart

​
Basic Usage

​
Queue a Local Function

def send_welcome_email(user_email):
    """Background task - sends email"""
    http.post("https://api.sendgrid.com/send", json={
        "to": user_email,
        "template": "welcome"
    })

def main():
    email = req.get("email")
    db.create_document("users", {"email": email})
    
    # Queue email (runs after return)
    queue.add("send_welcome_email", user_email=email)
    
    # Returns immediately
    return {"success": True}

​
Call Another Cloud Function

def main():
    order_id = create_order()

    # Call another deployed function in background
    queue.call_function("email-service",
                       template="order_confirmation",
                       order_id=order_id)

    queue.call_function("inventory-service",
                       action="reserve",
                       order_id=order_id)

    return {"order_id": order_id}

​
API Reference

​
queue.add(function_name, **params)

Queue a local function defined in the same file. 
queue.add("process_data",
         user_id="123",
         action="update")

​
queue.call_function(function_name, **params)

Call another deployed cloud function in the background. 
queue.call_function("analytics-service",
                   event="signup",
                   user_id="123")

​
Error Handling

Queue tasks that fail are not retried automatically. Handle errors inside the queued function: 
def risky_task(user_id):
    try:
        result = http.post("https://api.example.com/notify",
                         json={"user_id": user_id})
        print(f"Success: {user_id}")
    except Exception as e:
        print(f"Task failed: {e}")
        db.create_document("failed_tasks", {
            "user_id": user_id
        })

​
Common Patterns

​
User Registration

def main():
    email = req.get("email")
    user_id = create_user(email)

    queue.add("send_welcome_email", email=email)
    queue.add("create_preferences", user_id=user_id)
    queue.add("track_signup", user_id=user_id)

    return {"user_id": user_id}

​
Order Processing

def main():
    order_id = create_order(req.get("items"))

    queue.add("send_confirmation", order_id=order_id)
    queue.add("reserve_inventory", order_id=order_id)
    queue.call_function("shipping-service", order_id=order_id)

    return {"order_id": order_id}

​
Limitations

LimitValue
Max tasks per execution100
Task timeout20 seconds
PersistenceNot persisted (lost on restart)
Retry on failureNo automatic retry

​
When to Use Queue

Use queue for:
  • Sending emails after signup/purchase
  • Updating analytics after an action
  • Notifying external services
  • Any non-critical background work
Do not use queue for:
  • Critical operations that must succeed
  • Long-running tasks (use cron jobs)
  • Tasks that depend on each other in order
  • Recurring/scheduled tasks (use cron jobs)