## Overview
[QStash](https://upstash.com/docs/qstash/overall/getstarted) is a serverless message queue by Upstash. It lets you publish HTTP requests that get delivered reliably with automatic retries, delays, scheduling, and dead-letter queues.
Because QStash can publish to any HTTP endpoint, it works with AutoSend out of the box. You do not need a dedicated integration. QStash forwards your request (including the `Authorization` header) directly to the AutoSend API.
**This is useful when you want to:**
* Send emails reliably without blocking your main request
* Retry failed email sends automatically
* Schedule emails for a future time (e.g., 24 hours after signup)
* Queue high-volume sends without overwhelming your app
## Prerequisites
Before you start, make sure you have:
* An **AutoSend account** with an API key - get one at [autosend.com](https://autosend.com)
* An **Upstash account** with a QStash token - get one at [upstash.com](https://upstash.com)
* Node.js 18+ (or any environment that supports `fetch`)
## How It Works
QStash acts as a proxy between your app and the AutoSend API. Instead of calling `https://api.autosend.com/v1/mails/send` directly, you publish the request to QStash. QStash then delivers it to AutoSend, handling retries and scheduling for you.
Your App → QStash → AutoSend API → Email delivered
Your `Authorization: Bearer Thanks for signing up.
", }, }); console.log(res.messageId); // QStash message ID ``` `publishJSON` automatically sets `Content-Type: application/json` and serializes the body. **Response from QStash:** ```json theme={null} { "messageId": "msg_xxxxxxxxxxxxxxxx" } ```Here's what shipped...
", recipients: [ { email: "alice@example.com", name: "Alice" }, { email: "bob@example.com", name: "Bob" }, { email: "carol@example.com", name: "Carol" }, ], }, }); console.log(res.messageId); ```It's been 24 hours since you signed up. Need any help?
", }, }); ``` You can also schedule for an exact Unix timestamp using `notBefore`: ```javascript theme={null} const sendAt = Math.floor(Date.now() / 1000) + 3 * 24 * 60 * 60; // 3 days from now const res = await client.publishJSON({ url: "https://api.autosend.com/v1/mails/send", headers: { "Upstash-Forward-Authorization": `Bearer ${process.env.AUTOSEND_API_KEY}`, }, notBefore: sendAt, body: { from: { email: "hello@yourdomain.com", name: "Your Company" }, to: { email: "user@example.com" }, subject: "Your trial ends soon", html: "Your 7-day trial ends in 3 days.
", }, }); ``` ### Configure Retries By default, QStash retries failed requests 3 times. You can configure this: ```javascript theme={null} const res = await client.publishJSON({ url: "https://api.autosend.com/v1/mails/send", headers: { "Upstash-Forward-Authorization": `Bearer ${process.env.AUTOSEND_API_KEY}`, }, retries: 5, // retry up to 5 times on failure body: { from: { email: "hello@yourdomain.com", name: "Your Company" }, to: { email: "user@example.com" }, subject: "Important notification", html: "This message is important.
", }, }); ``` A retry is triggered when AutoSend returns a non-2xx HTTP response. QStash uses exponential backoff between retries. **How responses are handled:** * **2xx response** - Email successfully queued by AutoSend. No retry needed. * **Non-2xx response** - QStash retries automatically based on your retry configuration. Common errors that trigger retries include invalid API keys, unverified sender domains, missing required fields (`to`, `from`), and missing content (`html`, `text`, or `templateId`). ## Advanced Features ### Using Queues If you want concurrency control, for example limiting how many emails are sent per second, use a QStash queue with `enqueueJSON`. ```javascript theme={null} import { Client } from "@upstash/qstash"; const client = new Client({ token: process.env.QSTASH_TOKEN, }); const queue = client.queue({ queueName: "email-queue" }); const res = await queue.enqueueJSON({ url: "https://api.autosend.com/v1/mails/bulk", headers: { "Upstash-Forward-Authorization": `Bearer ${process.env.AUTOSEND_API_KEY}`, }, body: { from: { email: "hello@yourdomain.com", name: "Your Company" }, subject: "Campaign blast", html: "Big announcement!
", recipients: [ { email: "alice@example.com", name: "Alice" }, { email: "bob@example.com", name: "Bob" }, ], }, }); console.log(res.messageId); ``` Messages in a queue are processed in order. You can configure `parallelism` on the queue in your Upstash console. ### Using a Callback URL If you want to know when QStash has successfully delivered the email request to AutoSend, you can pass a `callback` URL. QStash will POST the response from AutoSend to this URL after delivery. ```javascript theme={null} const res = await client.publishJSON({ url: "https://api.autosend.com/v1/mails/send", headers: { "Upstash-Forward-Authorization": `Bearer ${process.env.AUTOSEND_API_KEY}`, }, callback: "https://yourapp.com/api/email-callback", failureCallback: "https://yourapp.com/api/email-failure", body: { from: { email: "hello@yourdomain.com", name: "Your Company" }, to: { email: "user@example.com" }, subject: "Hello", html: "Hello!
", }, }); ``` Your callback endpoint will receive a POST request containing the AutoSend API response body. **Example callback handler (Next.js App Router):** ```javascript theme={null} // app/api/email-callback/route.js export async function POST(req) { const body = await req.json(); // body is a QStash envelope, not the raw AutoSend response let autosendResponse; try { autosendResponse = JSON.parse(atob(body.body)); } catch { console.error("Failed to parse AutoSend response:", body.body); return Response.json({ ok: false }, { status: 400 }); } // autosendResponse = { success: true, data: { emailId: "em_xxx", ... } } console.log("Email delivered:", autosendResponse); return Response.json({ ok: true }); } ```Welcome to our platform!
", }, }); ``` If a message with the same `deduplicationId` was already published in the last 24 hours, QStash will reject the duplicate silently. ## Complete ExamplesWe're excited to have you.
If you have any questions, just reply to this email.
`, }, }); console.log("Email queued:", res.messageId); } catch (err) { // QStash publish failed - log and continue, don't block signup console.error("Failed to queue welcome email:", err); } return Response.json({ success: true }); } ```Hi ${user.name}, welcome to our platform!
`, deduplicationId: `onboard-day0-${user.id}`, }, { delay: "1d", // day 1 subject: "Getting started tips", html: `Hi ${user.name}, here are 3 things to try today...
`, deduplicationId: `onboard-day1-${user.id}`, }, { delay: "3d", // day 3 subject: "How's it going?", html: `Hi ${user.name}, just checking in. Need any help?
`, deduplicationId: `onboard-day3-${user.id}`, }, { delay: "7d", // day 7 subject: "Your first week", html: `You've been with us for a week, ${user.name}. Here's what's new...
`, deduplicationId: `onboard-day7-${user.id}`, }, ]; await Promise.all( emails.map(({ delay, subject, html, deduplicationId }) => qstash.publishJSON({ url: "https://api.autosend.com/v1/mails/send", headers: { "Upstash-Forward-Authorization": `Bearer ${process.env.AUTOSEND_API_KEY}`, }, delay, deduplicationId, body: { ...emailBase, subject, html, }, }) ) ); } ```