Migrate from AddressTwo to Mailchimp

Scoping and API key procurement

We audit the AddressTwo account for contact count, tag taxonomy, custom field definitions, note volume, and campaign membership lists. Simultaneously, we request the AddressTwo API key by emailing [email protected] on the customer's behalf. If the API key is not granted within one week, we fall back to the manual CSV export path, which may require a second request to AddressTwo support for a full account export including activities and notes. The scoping output is a written migration scope document with record counts per object and a Mailchimp Audience configuration plan.

Mailchimp Audience configuration

We create the destination Mailchimp Audience (or select an existing one) and pre-configure all required Merge Fields based on the AddressTwo custom field inventory. This includes COMPANY, any date or number Merge Fields, and any dropdown fields. We also configure the Mailchimp subscriber status settings (opt-in requirements, GDPR compliance fields) to match the AddressTwo consent model. Tags are not pre-created in Mailchimp; they are created dynamically during import from the AddressTwo tag array.

Data extraction and de-duplication

We extract Contacts, Tags, Notes, Activities, and campaign membership from AddressTwo. If the API key is granted, we pull data programmatically with rate-limit handling and a 30-second stagger between batch requests. If only CSV export is available, we process the CSV with field-level mapping. We run the de-duplication pass on email addresses (case-insensitive) to merge any duplicates created by AddressTwo's BCC sync issue, preserving the record with the most recent activity date as the surviving entry.

Subscriber import with merge field population

We import subscribers into Mailchimp using the Mailchimp API (Contacts endpoint) or CSV import, depending on volume. Each subscriber receives the standard Merge Fields (FNAME, LNAME, PHONE, COMPANY, ADDRESS) from the mapped AddressTwo fields. Tags are applied per subscriber via the Mailchimp Tags API after the base subscriber record is created. Subscriber status is set based on the AddressTwo opt-in field. Notes are added in a second pass using the Member Notes endpoint to avoid exceeding the import batch size.

Campaign membership and segment reconstruction

We create Mailchimp Tags for each AddressTwo mass email campaign and apply them to all members of that campaign. This reconstructs the campaign membership list as tag-based segments in Mailchimp. Open and click analytics from AddressTwo are not available in the export and do not transfer; the customer uses Mailchimp analytics going forward from the migration date. We document the tag-to-segment mapping in the migration handoff document.

Cutover, validation, and handoff

We run a final delta migration of any records modified during the migration window, then hand off the Mailchimp Audience as the active contact list. We validate by comparing Mailchimp subscriber count and tag distribution against the source AddressTwo report. We deliver the written migration report including record counts, excluded scope (Deals, Attachments), tag taxonomy, and a recommended Mailchimp Automation setup guide. We do not rebuild AddressTwo reminders or contact follow-up workflows in Mailchimp; these require rebuild in Mailchimp Automations as a separate task or engagement.