Update a subscriber in Mailchimp when a contact joins a list in Brevo

What each client fills in

Mailchimp: Audience ID

For example Audience → Settings → Audience name and defaults

Brevo: List ID

Contacts → Lists: the number beside the list’s name.

The accounts it needs

Each is the client’s own, stored encrypted and never copied between clients. Until one is added the client’s checklist shows it, and nothing runs.

• Brevo

  In the client’s Brevo: account menu → SMTP & API → API Keys → Generate a new API key.

• 

  In the client’s Mailchimp: Profile → Extras → API keys → Create A Key. The server prefix is the part after the dash (us21).

After you install it

It lands switched off. The client’s checklist holds exactly this:

1. Connect the client’s Brevo, for “A contact joins a list”
2. Connect the client’s Mailchimp, for “Update a subscriber”
3. Fill in Brevo: List ID (Contacts → Lists: the number beside the list’s name)
4. Fill in Mailchimp: Audience ID (For example Audience → Settings → Audience name and defaults)