Add to an audience in Mailchimp when a new contact is added in HubSpot

What each client fills in

Mailchimp: Audience ID

For example Audience → Settings → Audience name and defaults

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.

• 

  In the client’s HubSpot: Settings → Integrations → Private Apps (Legacy apps) → Create → scopes crm.objects.contacts.write, and for the triggers crm.objects.contacts.read, crm.objects.deals.read and tickets → copy the access token. A private app needs no HubSpot review.

• 

  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 HubSpot, for “A new contact is added”
2. Connect the client’s Mailchimp, for “Add to an audience”
3. Fill in Mailchimp: Audience ID (For example Audience → Settings → Audience name and defaults)