> ## Documentation Index
> Fetch the complete documentation index at: https://docs.partnero.com/llms.txt
> Use this file to discover all available pages before exploring further.
# Connect MailerLite to your newsletter referral program
When [creating a newsletter referral program](/knowledge-base/newsletter-referral-programs/how-to-setup-a-newsletter-referral-program), you will be prompted to select your email service provider.
To connect MailerLite:
1. Set up a newsletter referral program and select **MailerLite** or **MailerLite Classic** as the ESP upon creation:
2. Click **Create**.
3. Under **Program Settings**, click **Authorize** next to MailerLite integration:
4. Enter your MailerLite API key. [Here's how to find it.](https://www.mailerlite.com/help/where-to-find-the-mailerlite-api-key-groupid-and-documentation)
5. Click **Connect**.
6. Once connected, select the subscriber group that will participate in the referral program, as well as the destination group, where new subscribers will be added.
8. Click **Update**. Your subscriber list will be synchronized, and every subscriber will receive a unique referral link.
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