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

# Keplars

> Send transactional emails through Keplars based on Dodo Payments events.

## Introduction

Send professional transactional emails automatically when payment and subscription events occur. Deliver payment confirmations, subscription updates, and failure notifications through Keplars with no middleware server required. Dodo Payments calls the Keplars API directly using a JavaScript transformation handler.

<Info>
  This integration requires your Keplars API Key for authentication. Find it in the Keplars dashboard under **Settings → API Keys**, and verify a sender domain or address under **Domains**.
</Info>

## Getting Started

<Steps>
  <Step title="Open the Webhook Section">
    In your Dodo Payments dashboard, navigate to <b>Webhooks → + Add Endpoint</b> and expand the integrations dropdown.
  </Step>

  <Step title="Select Keplars">
    Choose the <b>Keplars</b> integration card.

    <Frame>
      <img src="https://mintcdn.com/dodopayments/tM0KgwbOo2xwg7zr/images/integrations/keplars/select.png?fit=max&auto=format&n=tM0KgwbOo2xwg7zr&q=85&s=776a4a2228efa0822b15b13d2baaf5bb" alt="Select the Keplars integration card" style={{ maxHeight: '500px', width: 'auto' }} width="1040" height="731" data-path="images/integrations/keplars/select.png" />
    </Frame>
  </Step>

  <Step title="Enter API Key">
    Provide your Keplars API Key. It is sent as a Bearer token on every request.

    <Frame>
      <img src="https://mintcdn.com/dodopayments/tM0KgwbOo2xwg7zr/images/integrations/keplars/api-key.png?fit=max&auto=format&n=tM0KgwbOo2xwg7zr&q=85&s=f3e0917155715d0587a6012c1bfd3f26" alt="Enter the Keplars API URL, API Key, and subscribe to events" style={{ maxHeight: '500px', width: 'auto' }} width="982" height="854" data-path="images/integrations/keplars/api-key.png" />
    </Frame>
  </Step>

  <Step title="Configure Transformation">
    Edit the transformation code to format emails for Keplars. Replace the placeholder sender address and template IDs with your own.
  </Step>

  <Step title="Test & Create">
    Test with sample payloads and click <b>Create</b> to activate email sending.
  </Step>

  <Step title="Done!">
    🎉 Payment events will now automatically trigger transactional emails via Keplars.
  </Step>
</Steps>

## Transformation Code Examples

Each handler sets `webhook.url` to the Keplars high-priority send endpoint and rewrites `webhook.payload` into a Keplars request (the API key is sent automatically as a Bearer token). Replace `payments@mail.yourdomain.com` with your verified sender and `your-keplars-*-template-id` with your actual template IDs.

<Warning>
  `to` must be an **array**, even for a single recipient. When using `template_id`, do **not** also send `subject` or `body`. The template supplies them.
</Warning>

### Payment Confirmation Email

```javascript payment_succeeded.js icon="js" expandable theme={null}
function handler(webhook) {
  if (webhook.eventType !== "payment.succeeded") return webhook;

  const data = webhook.payload.data || {};
  const paymentDate = new Date(webhook.payload.timestamp).toLocaleDateString("en-US", {
    year: "numeric", month: "long", day: "numeric",
  });

  webhook.url = "https://api.keplars.com/api/v1/send-email/high";
  webhook.payload = {
    to: [data.customer?.email],
    from: "payments@mail.yourdomain.com",
    template_id: "your-keplars-payment-success-template-id",
    params: {
      customer_name: data.customer?.name,
      amount: ((data.total_amount || 0) / 100).toFixed(2),
      currency: data.currency || "USD",
      payment_id: data.payment_id,
      payment_method: data.payment_method,
      payment_date: paymentDate,
    },
  };
  return webhook;
}
```

### Payment Failure Notification

```javascript payment_failed.js icon="js" expandable theme={null}
function handler(webhook) {
  if (webhook.eventType !== "payment.failed") return webhook;

  const data = webhook.payload.data || {};
  const paymentDate = new Date(webhook.payload.timestamp).toLocaleDateString("en-US", {
    year: "numeric", month: "long", day: "numeric",
  });

  webhook.url = "https://api.keplars.com/api/v1/send-email/high";
  webhook.payload = {
    to: [data.customer?.email],
    from: "payments@mail.yourdomain.com",
    template_id: "your-keplars-payment-failed-template-id",
    params: {
      customer_name: data.customer?.name,
      amount: ((data.total_amount || 0) / 100).toFixed(2),
      currency: data.currency || "USD",
      payment_id: data.payment_id,
      error_message: data.error_message || "Your payment could not be processed.",
      payment_date: paymentDate,
    },
  };
  return webhook;
}
```

### Subscription Welcome Email

```javascript subscription_active.js icon="js" expandable theme={null}
function handler(webhook) {
  if (webhook.eventType !== "subscription.active") return webhook;

  const data = webhook.payload.data || {};
  const nextBilling = data.next_billing_date
    ? new Date(data.next_billing_date).toLocaleDateString("en-US", {
        year: "numeric", month: "long", day: "numeric",
      })
    : "";

  webhook.url = "https://api.keplars.com/api/v1/send-email/high";
  webhook.payload = {
    to: [data.customer?.email],
    from: "payments@mail.yourdomain.com",
    template_id: "your-keplars-subscription-active-template-id",
    params: {
      customer_name: data.customer?.name,
      subscription_id: data.subscription_id,
      product_id: data.product_id,
      amount: ((data.recurring_pre_tax_amount || 0) / 100).toFixed(2),
      currency: data.currency || "USD",
      billing_interval: data.payment_frequency_interval || "month",
      next_billing_date: nextBilling,
    },
  };
  return webhook;
}
```

### Subscription Cancellation Email

```javascript subscription_cancelled.js icon="js" expandable theme={null}
function handler(webhook) {
  if (webhook.eventType !== "subscription.cancelled") return webhook;

  const data = webhook.payload.data || {};
  const cancellationDate = new Date(webhook.payload.timestamp).toLocaleDateString("en-US", {
    year: "numeric", month: "long", day: "numeric",
  });

  webhook.url = "https://api.keplars.com/api/v1/send-email/high";
  webhook.payload = {
    to: [data.customer?.email],
    from: "payments@mail.yourdomain.com",
    template_id: "your-keplars-subscription-cancelled-template-id",
    params: {
      customer_name: data.customer?.name,
      subscription_id: data.subscription_id,
      cancellation_date: cancellationDate,
    },
  };
  return webhook;
}
```

## Tips

* Use a verified sender domain or address for better deliverability.
* Create a dedicated Keplars template per event type so each email stays on-brand and on-message.
* Personalize each email by passing customer data like name, amount, and payment ID through `params`.
* Test in sandbox mode first. Sandbox sends are captured in the Keplars Test Inbox rather than delivered.

## Troubleshooting

<AccordionGroup>
  <Accordion title="Emails not being sent">
    * Verify your API key is correct and active in Keplars under **Settings → API Keys**.
    * Verify your sender domain or address is verified.
    * Dodo Payments shows the raw Keplars error response in the webhook delivery log. Check it for details.
  </Accordion>

  <Accordion title="Template not found">
    * The `template_id` in your handler must match an active template in your Keplars account. Verify the ID (and that it's active) in the dashboard.
  </Accordion>

  <Accordion title="Wrong event triggered">
    * Each handler checks `webhook.eventType` and returns early if it does not match. Make sure the correct events are subscribed on the Dodo Payments webhook endpoint.
  </Accordion>
</AccordionGroup>