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

# Resend

> Send transactional emails triggered by StellarTools payment events.

The Resend app connects your StellarTools organization to [Resend](https://resend.com), letting you send transactional emails when things happen to your customers — payments, subscriptions, refunds, and more.

With it you can:

* Send emails triggered by any StellarTools event
* Auto-sync new customers to a Resend audience
* Map each event type to a Resend email template
* View a live email log and delivery stats inside the dashboard

## Supported events

The app can trigger emails on any of the following StellarTools events:

| Event                    | When it fires                    |
| ------------------------ | -------------------------------- |
| `customer.created`       | A new customer is added          |
| `customer.updated`       | A customer's details change      |
| `customer.deleted`       | A customer is removed            |
| `payment_method.created` | A wallet is linked to a customer |
| `payment_method.deleted` | A wallet is removed              |
| `checkout.created`       | A checkout session is opened     |
| `payment.pending`        | A payment is initiated           |
| `payment.confirmed`      | A payment is confirmed on-chain  |
| `payment.failed`         | A payment fails                  |
| `refund.succeeded`       | A refund is processed            |
| `refund.failed`          | A refund attempt fails           |
| `subscription.created`   | A subscription starts            |
| `subscription.updated`   | A subscription changes           |
| `subscription.canceled`  | A subscription is canceled       |

## Connect your account

1. Open the Resend app from the StellarTools Marketplace.
2. Enter your Resend API key (starts with `re_`). The app validates it against your Resend account.
3. Choose a **sending domain**. If you have a verified domain in Resend, you can pick it here and set a custom `from` prefix (e.g. `noreply@yourdomain.com`). Without a verified domain, emails go out via `onboarding@resend.dev`, which can only reach addresses registered in your Resend account.
4. Click **Connect**. The app is now active.

To verify a sending domain, go to [resend.com/domains](https://resend.com/domains).

## Notification rules

Once connected, open the **Notification rules** section in the app dashboard. For each event type, you can assign a Resend email template. When that event fires in StellarTools, Resend sends the matched template to the customer.

Leave an event set to **None** to disable emails for it.

## Contact sync

Enable **Contact sync** to automatically add new StellarTools customers to your Resend audience when `customer.created` fires. Toggle it off to stop syncing.

## Disconnect

Click **Disconnect** in the top-right of the app dashboard. This removes your API key and pauses all email delivery.

## Examples

### Payment confirmed email

Send a receipt when a customer's payment goes through.

1. Create an email template in Resend for payment confirmations.
2. In the Resend app, open **Notification rules** and assign that template to `payment.confirmed`.

### Subscription welcome email

Send a welcome email when a customer starts a subscription.

1. Create an email template in Resend.
2. Assign it to `subscription.created` in **Notification rules**.

### Failed payment alert

Notify a customer when their payment fails so they can retry.

1. Create an email template in Resend for payment failures.
2. Assign it to `payment.failed` in **Notification rules**.

### Refund confirmation

Let customers know their refund was processed.

1. Create a refund confirmation template in Resend.
2. Assign it to `refund.succeeded` in **Notification rules**.