This guide is for users who already have a Mailchimp account and want to integrate it with OneSignal. If you don’t have a Mailchimp account, consider using OneSignal Email instead.

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Requirements

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Setup

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1. Configure your domain for email

Go to the Mailchimp Transactional Email Domains page and add your domain if it hasn’t been added already.

Add domain

After adding your domain:
  • Click View DKIM/SPF Setup Instructions to get your DNS records.
  • Optionally verify ownership via email under View details.

View DKIM/SPF Setup Instructions

Update your DNS records with your DNS provider. Follow Mailchimp’s setup guide if needed. Mailchimp may take up to 48 hours to verify your domain. You’ll receive a confirmation email once complete.

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2. Create API Key

In the Transactional Email Settings, click + New API Key.

Create API Key

You can name it something like OneSignal API Key.

Name the API Key

Once created:
  • Copy the API key securely
  • Note your SMTP Username

Copy the API key and SMTP Username

Treat your API key like a password — keep it secure and never share it.
Enable the following permissions to ensure compatibility with OneSignal:

API Key Permissions

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3. Enable email messaging in OneSignal

  1. In your OneSignal dashboard, go to Settings > Platforms > Email.

Enable Email Messaging

  1. Select Mailchimp as your provider and enter the API key and SMTP username.

Select Mailchimp and enter credentials

Configure Mailchimp email settings

  1. Set your default sender name and email address.

Configure default sender info

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4. Send a test email

Go to OneSignal > Messages > Email and click New Email.
  • Add a subject line
  • Click Send Test Email
  • Enter your email address and click Send Test Message

Send Test Email

You should receive your test email shortly.
Having issues? Check the Email FAQ or email support@onesignal.com.For faster assistance, include:
  • Your OneSignal App ID
  • Detailed issue description, logs, and screenshots
  • Steps to reproduce

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Optional: Generate API key from Mailchimp Dashboard

If you are generating an API key from the main Mailchimp account dashboard:
  1. Click your avatar in the top-right corner.

Open profile menu

  1. Go to Account & Billing.

Navigate to Account & Billing

  1. Click Extras > API Keys.

Access API Key section

  1. Click Create A Key.

Create a new API key

  1. Name your key and click Generate Key.

Generate key

  1. Copy the API key securely.

Copy key to clipboard

✅ Email setup complete!Next steps: