In MailChimp: generating the API key

Requirements: a MailChimp account (section 2).

1. Click your profile icon and choose Account.
2. Open the Extras dropdown and select API keys.
3. In the “Your API Keys” section, click Create A Key.
4. Give it a recognizable name — for example the app that will use it, never a generic one like “test”.
5. Click Generate Key and then Copy Key to Clipboard — MailChimp only shows the full key immediately after generating it; from then on, your key list will only show its name and its first four digits.

Note — The datacenter is embedded in the key itself

Unlike other integrations, there’s no need to state the datacenter separately: it’s encoded in the key’s own suffix (for example, the -us6 at the end) — the Platform detects it automatically when connecting.

Notice — Transactional emails: a separate, optional key

If you also want the “Event → transactional email” action (section 5) to work, you need a Mandrill API key (Mailchimp Transactional) — a product and billing DIFFERENT from your Marketing account, with its own sign-up. Without that key, the integration syncs contacts and tags normally; that specific action just doesn’t get to send anything.

Verified against MailChimp’s official documentation (mailchimp.com/help/about-api-keys/, checked on September 5, 2026).