> ## Documentation Index
> Fetch the complete documentation index at: https://docs.booper.dev/llms.txt
> Use this file to discover all available pages before exploring further.

# Delayed welcome email

> Send a welcome email 45 minutes after signup

### Overview

Sometimes rather than sending a welcome email to new users *immediately*, it's nice to delay it.

(Some email APIs support this out of the box, but for the sake of this example, let's assume they don't.)

We're going to use [Resend](http://resend.com/) as our email API, because we're big fans!

### Getting your Resend API key

Before we can set up our scheduled email, you'll need an [API key](https://resend.com/api-keys) from Resend.

Sign up for a free account here: [https://resend.com/signup](https://resend.com/signup)

### Scheduling your welcome email

Once we have our Resend API key, we can send a `POST` request to `https://api.resend.com/emails` with the following email parameters:

```js theme={null}
const email = {
  // If you want to send from your own domain, you'll have to verify
  // your domain in the Resend dashboard: https://resend.com/domains
  from: "Example <welcome@resend.dev>",
  // The email address of the user that just signed up:
  to: user.email,
  subject: "Welcome to Example Inc!",
  html:
    "<p>Thanks for signing up!</p>" +
    "<p>Check out our docs to get started: https://docs.example.com</p>" +
    "<p>Best,<br />Alex</p>",
};
```

Here's how it might look in the code after a new user signs up for an account:

```ts theme={null}
import Scheduler from "@booper/scheduler";

const BOOPER_API_KEY = process.env.BOOPER_API_KEY;
const RESEND_API_KEY = process.env.RESEND_API_KEY;

const scheduler = new Scheduler({ apiKey: BOOPER_API_KEY });

async function register(user) {
  // ...
  // handle user registration logic
  // ...

  await scheduler.jobs.create({
    method: "post",
    url: "https://api.resend.com/emails",
    headers: {
      Authorization: `Bearer ${RESEND_API_KEY}`,
    },
    body: {
      from: "Example <welcome@resend.dev>",
      to: user.email,
      subject: "Welcome to Example Inc!",
      html:
        "<p>Thanks for signing up!</p>" +
        "<p>Check out our docs to get started: https://docs.example.com</p>" +
        "<p>Best,<br />Alex</p>",
    },
    schedule_in: [45, "minutes"],
    idempotency_key: `${user.email}:welcome`,
  });
}
```

<Info>
  Don't forget to pass in your `RESEND_API_KEY` in the `Authorization` header
</Info>

This will schedule an email to be sent to `user.email` in 45 minutes after signing up.

### Optional: Ensuring idempotency

Booper also features an option to ensure **idempotency**, meaning we can set a key that is used to enforce uniqueness.

In other words, if we want to send an email to Jane and make sure it's only sent *once*, we could set the `idempotency_key` to some combination of Jane's unique ID with the name of the email template (e.g. `jane.welcome`) to force any future scheduled emails with the same `idempotency_key` to be ignored.