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

# Step 9: Resend (Optional)

> Configure email service for magic link authentication

<Note>Note that if you want to use magic link sign-in, this is a required step.</Note>

Next, you'll need to set up Resend for transactional emails (e.g. magic link emails):

## Setup Instructions

1. Sign up for Resend and [create your API key here](https://resend.com/api-keys).
2. Copy the API key into your `.env` file as the `RESEND_API_KEY` environment variable.

```TypeScript .env theme={null}
RESEND_API_KEY=your_resend_api_key
```

3. You'll then need to set up and verify your domain by [following this guide here](https://resend.com/docs/dashboard/domains/introduction).

## Next Steps

Once you've completed the Resend setup (or skipped it if not using magic links), proceed to [Step 10: Deploy to Vercel](/open-source/step-10-deploy-vercel) to deploy your application.