Migrate from Civicrm to Mailchimp

CiviCRM Individual contact records map to Mailchimp subscribers. We extract the primary email address (is_bulkmail = 1 or the first email chronologically if no bulk flag is set), first name, last name, and any CiviCRM-registered addresses. Contacts without any email address are excluded and listed in a separate skip report. The primary-email-only constraint is resolved during extraction; contacts with multiple emails must have a primary designated before migration begins, or we flag them for admin decision.

CiviCRM Organization contacts map to Mailchimp subscribers with the organization name populating a COMPANY merge field. The organization contact's primary email becomes the subscriber address. Household contacts map similarly, with household name in COMPANY and member first/last names in FNAME/LNAME. Relationship data (spousal, household membership) does not migrate because Mailchimp has no relational contact model.

Single-record CiviCRM custom fields attached to Contact (via custom.* in APIv4) map to Mailchimp merge fields. Field type mapping: CiviCRM Text maps to Mailchimp TEXT; Date maps to DATE; Integer and Number map to NUMBER; Checkbox maps to EMAIL or TEXT depending on whether the custom field represents a boolean preference; Select/Radio maps to RADIO; Multi-Select/Checkbox maps to ZIP or TEXT with comma-separated values. Merge field names must be uppercase ASCII; we strip spaces and truncate to Mailchimp's 30-character limit.

Multi-record custom groups (prefixed Custom_ in APIv4) do not map cleanly to Mailchimp's flat merge-field schema. We extract the first record as a set of merge fields and flag remaining records for admin decision: they can be appended as pipe-delimited text in a single merge field, or archived outside Mailchimp if the historical detail matters.

CiviCRM Groups map to Mailchimp Segments. The static group membership list (GroupContact records) becomes the Segment membership. We preserve the group name as the Segment name. Mailchimp Segments are flat — no nested hierarchy — so parent-child group relationships in CiviCRM become sibling Segments or are flattened into a single Segment with a naming convention that conveys the hierarchy.

CiviCRM smart groups (dynamic criteria-based membership) cannot be reproduced in Mailchimp without re-running the original query logic against migrated data. We export the current smart group membership as a static list at migration time and create a Mailchimp Segment from that snapshot. We document the original smart group criteria so the customer's admin can rebuild Mailchimp's dynamic segmentation using Mailchimp's own segmentation builder against the migrated data.

CiviCRM Tags (flat labels on any entity) map directly to Mailchimp Tags on the contact record. Tags are preserved as strings. Multi-entity tagging (tagging on activities, events, etc.) does not migrate because Mailchimp tags are contact-level only; we document the tag counts per contact as a note field if the tag volume is significant.

CiviCRM Relationship records (household member, employee-employer, spousal, etc.) have no Mailchimp equivalent. Relationships are contact-to-contact links that Mailchimp does not store. We do not migrate Relationships. If organizational relationship data is business-critical, we recommend exporting it as a CSV for external storage or reference.

CiviCRM Activities (calls, emails, meetings, tasks, case notes) are engagement records with no Mailchimp equivalent. Mailchimp stores campaign delivery statistics (sends, opens, clicks, unsubscribes) but not a timeline of internal outreach history. We do not migrate Activities. We document the activity record counts per contact as a reconciliation reference.

CiviCRM Contributions (donation amount, financial type, payment instrument, receive date) are financial records with no Mailchimp object equivalent. Mailchimp does not store monetary data. We do not migrate Contributions. If donation history matters for segmentation, we can map contribution records to Tags or Merge Fields (e.g., Lifetime_Donor = Yes, Largest_Gift = $500) during extraction as a derived transformation, but raw financial records are not migrated.