Background Jobs

​

When do you need background jobs

Background jobs are essential for executing tasks that are too time-consuming to run in the main execution thread without affecting the user experience.

These tasks might include data processing, sending batch emails, performing scheduled maintenance, or any other operations that are not immediately required to respond to user requests.

Utilizing background jobs allows your application to remain responsive and scalable, handling more requests simultaneously by offloading heavy lifting to background processes.

​

How to use QStash for background jobs

QStash provides a simple and efficient way to run background jobs, you can understand it as a 2 step process:

1. Public API Create a public API endpoint within your application. The endpoint should contain the logic for the background job.

2. QStash Request Invoke QStash to start/schedule the execution of the API endpoint.

Here’s what this looks like in a simple Next.js application:

"use client"

export default function Home() {
  async function handleClick() {
    // Send a request to our server to start the background job.
    // For proper error handling, refer to the quick start.
    // Note: This can also be a server action instead of a route handler
    await fetch("/api/start-email-job", {
      method: "POST",
      body: JSON.stringify({
        users: ["a@gmail.com", "b@gmail.com", "c.gmail.com"]
      }),
    })

  }

  return (
    <main>
      <button onClick={handleClick}>Run background job</button>
    </main>
  );
}

To better understand the application, let’s break it down:

1. Client: The client application contains a button that, when clicked, sends a request to the server to start the background job.
2. Next.js server: The first endpoint, /api/start-email-job, is invoked by the client to start the background job.
3. QStash: The QStash client is used to invoke the /api/send-email endpoint, which contains the logic for the background job.

Here is a visual representation of the process:

To view a more detailed Next.js quick start guide for setting up QStash, refer to the quick start guide.

It’s also possible to schedule a background job to run at a later time using schedules.

If you’d like to invoke another endpoint when the background job is complete, you can use callbacks.