---
title: "Auth0 Integration"
slug: auth0-integration
description: "Send Auth0 transactional emails through Resend using the official integration."
created_at: "2026-05-07"
updated_at: "2026-05-07"
image: https://cdn.resend.com/posts/auth0-integration.png
humans: ["christina-martinez"]
---

Authentication at scale is a difficult challenge, and Auth0 has made it approachable for teams of every size. Auth0 includes a built-in email provider, but also supports custom providers. 

Today, **Auth0 adds Resend as a supported email provider**.

<blockquote>
  We’re excited to bring the power and simplicity of Resend to our customers. This partnership makes it incredibly easy for developers to level-up their email delivery, whether they need a quick five-minute setup or a fully customized solution.
  <div className="quote-metadata">
    <div className="quote-avatars">
      <div className="quote-avatar quote-avatar-author">
        <img
          alt="Ian Hassard"
          src="/static/avatars/ian-hassard.jpeg"
          width="40"
          height="40"
        />
      </div>
    </div>
    <span className="quote-author">
      <span className="quote-author-name">Ian Hassard</span>
      <span className="quote-author-job">VP, Product Management, Auth0</span>
    </span>
  </div>
</blockquote>

Crucial emails, like verification codes, password resets, and more, need to be delivered to inboxes quickly and reliably. With the Resend connector, you can start sending these emails in just a few minutes.

Prefer a video walkthrough? 

<YouTube videoId="-xlz8xVN3Rc" />

## Getting started

Before connecting Auth0 to Resend, you'll need two things:

1. A **verified domain** in your [Resend dashboard](https://resend.com/domains). Auth0 will send from this domain, so make sure it matches your Auth0 custom domain.
2. An **API key** from your [API Keys page](https://resend.com/api-keys).

## Basic configuration

In the Auth0 Dashboard, go to **Branding > Email Provider**, toggle on **Use my own email provider**, and select **Resend**.

- Set the **From** address to match your Resend verified domain.
- Enter your Resend API key

<video src="https://cdn.resend.com/posts/auth0-integration-1.mp4" className="extraWidth" autoPlay loop muted playsInline />

To test that it's working, click **Send Test Email**. The email should be sent, and will also appear in your Resend dashboard.

## Using Auth0 Actions

For more control over delivery, like per-organization sender addresses, conditional routing, or custom logic, you can use an Auth0 Action instead.

In the Auth0 Dashboard, go to **Actions > Library**, create a new Custom action, and add `resend` as a dependency. Store your API key as a secret named `RESEND_API_KEY`.

<video src="https://cdn.resend.com/posts/auth0-integration-2.mp4" className="extraWidth" autoPlay loop muted playsInline />

Here's a working example that sends a security alert on first login:

```javascript
const { Resend } = require('resend');

exports.onExecutePostLogin = async (event, api) => {
  const resend = new Resend(event.secrets.RESEND_API_KEY);

  if (event.stats.logins_count === 1) {
    await resend.emails.send({
      from: 'Security <security@yourdomain.com>',
      to: event.user.email,
      subject: 'New login detected',
      html: `<p>Hi ${event.user.name}, a new login was detected from ${event.request.ip}.</p>`,
    });
  }
};
```

Deploy it by adding the action to the **Post Login** trigger under **Actions > Triggers**.

<video src="https://cdn.resend.com/posts/auth0-integration-3.mp4" className="extraWidth" autoPlay loop muted playsInline />

## Customizing Email Templates

To customize the email templates that Auth0 sends out, go to **Branding > Email Templates** in the Auth0 Dashboard and make your changes to the existing templates.

For more advanced templating, consider our guides on [React Email](/docs/send-with-auth0#react-email) or [Resend Templates](/docs/send-with-auth0#resend-templates) within Auth0.

## Start today

Check out [the Auth0 docs](https://auth0.com/docs/customize/email/smtp-email-providers/resend) for the full setup guide.

We're excited to see what you build with Resend and Auth0!