pmpro-mailchimp

Integrate Mailchimp with Paid Memberships Pro. Automatically subscribe members to audiences based on their membership level and allow members to opt-in to lists at checkout or by editing their profile. Maintained by strangerstudios on GitHub, where it has earned 26 stars from the community.

It's actively developed around wordpress, paid-memberships-pro, mailchimp, and is a solid reference for anyone building with these tools.