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Prerequisites

To get the most out of this guide, you’ll need to:

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1. Get the Resend SMTP credentials

When configuring your SMTP integration, you’ll need to use the following credentials:
  • Host: smtp.resend.com
  • Port: 465
  • Username: resend
  • Password: YOUR_API_KEY

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2. Integrate with Customer.io SMTP

After logging into your Customer.io account, you’ll need to enable the SMTP integration.
  1. Go to Settings > Workspace Settings.
Customer.io SMTP - Workspace Settings
  1. Go to the Messaging tab and select Email.
Customer.io SMTP - Email
  1. Select the Custom SMTP tab and click Add Custom SMTP Server.
Customer.io SMTP - Add Custom SMTP Server
  1. Select Other SMTP and click Continue to set up.
Customer.io SMTP - Other SMTP
  1. Copy-and-paste the SMTP credentials from Resend to Customer.io.
Customer.io SMTP integration