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

# Switching to Resend Forge

> Configure Resend to use their own email sending infrastructure instead of SES

<Info>
  **Created**: 2026-09-21

  **Last Updated**: 2026-09-21

  **Author**: Pieter Beulque
</Info>

## Summary

Resend is moving from their SES wrapper to their own sending infrastructure.
After running this test in sandbox for a few weeks, we'll now switch our production
sending infrastructure to it.

## Context

So far, sandbox has sent 17,900 emails through Resend Forge with a tiny 0.53% bounce rate.
All the bounces were not reputation related, but just "mailbox full", "address does not exist".

Also, the aggregated metrics as a whole for Forge are pretty good:

* 99.8% of email deliveries on the new engine are delivered within 3 minutes vs 97.9% on the old one
* P50 delivery time is 23% faster
* Receivers defer/delay the new engine far less: 0.8% of sends delayed vs 19.9% on the old one

## Implementation

Resend Forge can be enabled through the Resend dashboard, and requires an additional DNS record:

```
CNAME mail.notifications.polar.sh send.forge.rmta.net
```

We will add this through Terraform in the `render_service` module, like so:

```
resource "cloudflare_dns_record" "resend_mail" {
  zone_id = var.resend_domain.zone_id
  name    = "mail.${var.email_from_domain}"
  type    = "CNAME"
  content = "send.forge.rmta.net"
  proxied = false
  ttl     = 1
}
```

The sandbox DNS record was added on Cloudflare directly, so we'll have to import
that record into Terraform as well to make the plan work.

## Security considerations

Always fill this in. If a point does not apply, write "None" and a short why.

* **Data in and out** — No changes. Underlying email data won't touch SES anymore, so one less subprocessor
* **Who can access it** — No changes. Underlying email data won't touch SES anymore, so one less subprocessor
* **Data we store** — No changes. Underlying email data won't touch SES anymore, so one less subprocessor
* **Risks** — No security risks