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Mailchimp

Keep a Mailchimp audience in sync with B1 automatically: people flow in with their name, email, and phone; group and list membership becomes Mailchimp tags; deleted people are archived. The sync is built into B1 — no third-party service, no per-task metering, and changes arrive in near-realtime rather than on a nightly schedule.

Before You Begin

  • A Mailchimp account with the audience you want B1 to manage
  • A Mailchimp API key (Mailchimp: profile icon → Account & billing → Extras → API keys)
  • Your Audience ID (Mailchimp: Audience → Settings → Audience name and defaults)
  • A B1Admin user with Edit Settings permission

What Syncs​

B1 changeMailchimp effect
Person added or updatedSubscriber added/updated (first name, last name, phone; new subscribers arrive as subscribed)
Person deleted (or GDPR-erased)Subscriber archived
Person joins a groupTag named after the group added
Person leaves a groupThat tag removed
Person enters a saved listTag named after the list added
Person leaves a saved listThat tag removed

Saved lists are usually the better tag source. A B1 saved list is a rule-based audience that re-evaluates itself — "everyone at the North campus," "members who opted into pastoral emails." Point your Mailchimp segments at list tags and the sync maintains them; use group tags for ministry-team mailings.

The sync is one-way (B1 → Mailchimp) and only touches Mailchimp's standard fields, so it can't conflict with merge fields or segments you manage inside Mailchimp.

Setup​

  1. In B1Admin go to Settings → Developer → Webhooks → Add Webhook.
  2. Set Connector Type to Mailchimp.
  3. Paste your Mailchimp API Key and Audience ID. The key is stored encrypted and never shown again.
  4. The relevant events are pre-selected; uncheck any you don't want (e.g. leave person events on but skip group tags).
  5. Save. B1 verifies the key and audience against Mailchimp before accepting — a typo fails immediately with a reason.

Use Send Test at any time to re-verify the connection. Every sync attempt is logged in the webhook's delivery history with Mailchimp's actual response, and failed deliveries retry automatically with backoff for about five days.

Initial Import​

The connector syncs changes from the moment it's on; it doesn't backfill your existing directory. For setup day:

  1. In B1Admin go to People, search for the people you want (or run a saved list), and click Export to download a CSV.
  2. In Mailchimp use Audience → Import contacts to load the CSV, applying any tags during import.

Doing the initial load through Mailchimp's importer keeps you in control of the consent question — only import people who have actually agreed to receive your emails. Bulk-importing a whole directory as subscribed contacts can violate Mailchimp's terms and anti-spam law (CAN-SPAM/GDPR).

Limits & Notes​

  • One-way sync. Unsubscribes, bounces, and edits made in Mailchimp do not flow back to B1. Someone who unsubscribes in Mailchimp can still receive email sent directly from B1 — treat Mailchimp as the source of truth for bulk-mail consent.
  • People without an email address are skipped (logged as such in the delivery history) — Mailchimp subscribers are keyed by email.
  • Email address changes create a new subscriber. Mailchimp identifies people by email, so changing someone's email in B1 adds them under the new address; the old subscriber stays until you archive it in Mailchimp.
  • Only standard fields sync — first name, last name, phone. Membership status, campus, and custom B1 fields don't map to Mailchimp merge fields in this version; use list tags to segment instead.
  • Tag names are the group/list names. Renaming a group or list starts tagging under the new name; the old tag remains on existing subscribers until removed in Mailchimp.
  • Mailchimp's contact limits still apply — a sync that pushes a free-tier audience past its cap will log Member limit reached errors in the delivery history.

Other Recipes (Zapier / Make)​

Anything beyond audience sync — tagging givers on donation.created, a Mailchimp → B1 reverse direction, or syncing to a different email platform entirely (Constant Contact, Brevo, etc.) — is still available through Zapier or Make, which trigger on the same webhook events:

  • Tag givers: B1 New Donation → B1 Find Person → Mailchimp Add Subscriber to Tag (Gave-2026)
  • Two-way: Mailchimp New Subscriber → B1 Create Person

If you previously wired person/group sync through Zapier, switch those Zaps off after enabling the native connector — running both double-processes every event and burns Zapier tasks for nothing.

Troubleshooting​

  • Save fails with "Mailchimp rejected the API key" — the key was revoked or mistyped. Keys must end in a data-center suffix like -us21.
  • Save fails with "audience not found" — the Audience ID doesn't exist under that account. Copy it from Audience → Settings → Audience name and defaults (it's not the audience's name).
  • A person never appeared in Mailchimp — check the webhook's delivery history. "Skipped: person has no email address" means exactly that; a 4xx from Mailchimp shows the reason in the response body.
  • Deliveries stopped entirely — after repeated exhausted deliveries the webhook auto-disables. Fix the cause (usually a revoked key), re-enable it, and use Send Test to confirm.

See Also​