QStash is a robust message queue and task-scheduling service that integrates perfectly with Next.js. This guide will show you how to use QStash in your Next.js projects, including a quickstart and a complete example.

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Quickstart

At its core, each QStash message contains two pieces of information:

  • URL (which endpoint to call)
  • Request body (e.g. IDs of items you want to process)

The following endpoint could be used to upload an image and then asynchronously queue a processing task to optimize the image in the background.

upload-image/route.ts
import { Client } from "@upstash/qstash"
import { NextResponse } from "next/server"

const client = new Client({ token: process.env.QSTASH_TOKEN! })

export const POST = async (req: Request) => {
  // Image uploading logic

  // 👇 Once uploading is done, queue an image processing task
  const result = await client.publishJSON({
    url: "https://your-api-endpoint.com/process-image",
    body: { imageId: "123" },
  })

  return NextResponse.json({
    message: "Image queued for processing!",
    qstashMessageId: result.messageId,
  })
}

Note that the URL needs to be publically available for QStash to call, either as a deployed project or by developing with QStash locally.

Because QStash calls our image processing task, we get automatic retries whenever the API throws an error. These retries make our function very reliable. We also let the user know immediately that their image has been successfully queued.

Now, let’s receive the QStash message in our image processing endpoint:

process-image/route.ts
import { verifySignatureAppRouter } from "@upstash/qstash/nextjs"

// 👇 Verify that this messages comes from QStash
export const POST = verifySignatureAppRouter(async (req: Request) => {
  const body = await req.json()
  const { imageId } = body as { imageId: string }

  // Image processing logic, i.e. using sharp

  return new Response(`Image with id "${imageId}" processed successfully.`)
})
.env
# Copy all three from your QStash dashboard
QSTASH_TOKEN=
QSTASH_CURRENT_SIGNING_KEY=
QSTASH_NEXT_SIGNING_KEY=

Just like that, we set up a reliable and asynchronous image processing system in Next.js. The same logic works for email queues, reliable webhook processing, long-running report generations and many more.

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Example project

  • Create an Upstash account and get your QStash token
  • Node.js installed
1

Create Next.js app and install QStash

npx create-next-app@latest qstash-bg-job

cd qstash-bg-job

npm install @upstash/qstash

npm run dev
2

Create UI

After removing the default content in src/app/page.tsx, let’s create a simple UI to trigger the background job using a button.

src/app/page.tsx
"use client"

export default function Home() {
  return (
    <main className="flex h-lvh items-center justify-center">
      <button
        onClick={handleClick}
        className="btn btn-primary w-1/2 h-56 bg-green-500 text-xl sm:text-3xl rounded-lg hover:bg-green-600"
      >
        Start Background Job
      </button>
    </main>
  )
}
3

Start Background Job

We can use QStash to start a background job by calling the publishJSON method. In this example, we’re using Next.js server actions, but you can also use route handlers.

Since we don’t have our public API endpoint yet, we can use Request Catcher to test the background job. This will eventually be replaced with our own API endpoint.

src/app/actions.ts
"use server"
import { Client } from "@upstash/qstash"

const qstashClient = new Client({
  // Add your token to a .env file
  token: process.env.QSTASH_TOKEN!,
})

export async function startBackgroundJob() {
  await qstashClient.publishJSON({
    url: "https://firstqstashmessage.requestcatcher.com/test",
    body: {
      hello: "world",
    },
  })
}

Now let’s invoke the startBackgroundJob function when the button is clicked.

src/app/page.tsx
"use client"
import { startBackgroundJob } from "@/app/actions"

export default function Home() {
  async function handleClick() {
    await startBackgroundJob()
  }

  return (
    <main className="flex h-lvh items-center justify-center">
      <button
        onClick={handleClick}
        className="btn btn-primary w-1/2 h-56 bg-green-500 text-xl sm:text-3xl rounded-lg hover:bg-green-600"
      >
        Start Background Job
      </button>
    </main>
  )
}

To test the background job, click the button and check the Request Catcher for the incoming request.

4

Create your own endpoint

Now that we know QStash is working, let’s create our own endpoint to handle a background job. This is the endpoint that will be invoked by QStash.

This job will be responsible for sending 10 requests, each with a 500ms delay. Since we’re deploying to Vercel, we have to be cautious of the time limit for serverless functions.

src/app/api/long-task/route.ts
export async function POST(request: Request) {
  const data = await request.json()

  for (let i = 0; i < 10; i++) {
    await fetch("https://firstqstashmessage.requestcatcher.com/test", {
      method: "POST",
      body: JSON.stringify(data),
      headers: { "Content-Type": "application/json" },
    })
    await new Promise((resolve) => setTimeout(resolve, 500))
  }

  return Response.json({ success: true })
}

Now let’s update our startBackgroundJob function to use our new endpoint.

There’s 1 problem: our endpoint is not public. We need to make it public so that QStash can call it. We have 2 options:

  1. Deploy our application to a platform like Vercel and use the public URL.
  2. Create a local tunnel to test the endpoint locally.

For the purpose, of this tutorial, I’ll deploy the application to Vercel, but feel free to use a local tunnel if you prefer.

Now that we have a public URL, we can update the URL.

src/app/actions.ts
"use server"
import { Client } from "@upstash/qstash"

const qstashClient = new Client({
  token: process.env.QSTASH_TOKEN!,
})

export async function startBackgroundJob() {
  await qstashClient.publishJSON({
    // Replace with your public URL
    url: "https://qstash-bg-job.vercel.app/api/long-task",
    body: {
      hello: "world",
    },
  })
}

And voila! You’ve created a Next.js app that calls a long-running background job using QStash.

5

Error catching and security

QStash is a great way to handle background jobs, but it’s important to remember that it’s a public API. This means that anyone can call your endpoint. Make sure to add security measures to your endpoint to ensure that QStash is the sender of the request.

Luckily, our SDK provides a way to verify the sender of the request. Make sure to get your signing keys from the QStash console and add them to your environment variables. The verifySignatureAppRouter will try to load QSTASH_CURRENT_SIGNING_KEY and QSTASH_NEXT_SIGNING_KEY from the environment. If one of them is missing, an error is thrown.

src/app/api/long-task/route.ts
import { verifySignatureAppRouter } from "@upstash/qstash/nextjs"

async function handler(request: Request) {
  const data = await request.json()

  for (let i = 0; i < 10; i++) {
    await fetch("https://firstqstashmessage.requestcatcher.com/test", {
      method: "POST",
      body: JSON.stringify(data),
      headers: { "Content-Type": "application/json" },
    })
    await new Promise((resolve) => setTimeout(resolve, 500))
  }

  return Response.json({ success: true })
}

export const POST = verifySignatureAppRouter(handler)

Let’s also add error catching to our action and a loading state to our UI.

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Result

We have now created a Next.js app that calls a long-running background job using QStash! Here’s the app in action:

We can also view the logs on Vercel and QStash

And the code for the 3 files we created:

Now, go ahead and try it out for yourself! Try using some of the other features of QStash, like schedules, callbacks, and URL Groups.

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