Where to Find Your API Key
Log in to your Mailchimp account.
Click your profile icon in the bottom left and select Account & billing.
Go to Extras → API Keys.
Click Create A Key if you do not have one.
Copy the API key. It will look something like abc123def456-us14.
The Data Center Prefix
Your Mailchimp data center is the part after the dash in your API key. For example, if your key ends in -us14, your data center is us14. The plugin extracts this automatically from the API key, so you do not need to enter it separately.
Finding Your List/Audience ID
In Mailchimp, go to Audience from the main menu.
Click All Contacts.
Click Settings → Audience name and defaults.
Scroll down to find Audience ID. It looks like abc1234def.
Tip: The Mailchimp integration is GDPR compliant — it does not force resubscribe existing contacts. If someone who previously unsubscribed enters their email, they will not be re-added automatically. This complies with anti-spam regulations.