SumUp POS’s Mailchimp integration syncs your SumUp POS customer list with a Mailchimp marketing list. Customer names and email addresses will be synced to your chosen list if the customer is active and has opted-in to receive marketing material. Customers will be unsubscribed from the list if they become inactive, opt out of marketing or delete their SumUp POS account via a GDPR request.


To enable the integration you will need an API key and an existing Mailchimp list:

  • Visit the dropdown in the top right, then “Account” option.
  • Go to the “Extras” dropdown, then “API keys” option.
  • Click “Create a Key”.
  • Copy the newly created key from the table.
  • Go to the SumUp POS Mailchimp integration page.
  • Set the API key created in Mailchimp and enter the name of the Mailchimp list where the SumUp POS customers should be added.

Update process

The following process is run daily once the integration has been enabled.

Subscribing users

Customer records will be added to the Mailchimp list when all the following are true:

  • No record exists for the customer email address in Mailchimp
  • The customer record in SumUp POS is active and the opt-in setting is enabled

Unsubscribing users

Customer records will be removed from the mailchimp list when all the following are true:

  • A record exists in Mailchimp with the customer email address
  • The Mailchimp record is in the "subscribed" state
  • The SumUp POS customer record is inactive or the opt-in setting is disabled

If a Mailchimp record has no matching SumUp POS customer (based on the email), no action will be taken.

Using existing lists

You can connect the integration to an existing list, for example you might be maintaining a single list for all customer sources or you may have migrated from another POS system. Duplicates will not be created and existing records will not be removed unless they meet the removal criteria described above.

Check bulk-imported data

If you have bulk-imported customers from another system and the "opt-in" field was disabled in the import, this would make the customer records applicable for removal from Mailchimp in the next sync (because marketing consent has not been given). Please ensure the "opt-in" field is set correctly when bulk-importing customer records.


The are a few reasons why new POS customers wont be synced to Mailchimp:

  • Mailchimp believes the email is not real (eg just consists of random characters).
  • The selected Mailchimp list has required merge fields that we do not populate (anything other than |NAME|).
  • The customer has not opted in to email marketing in SumUp POS (see unsubscribe criteria above).
  • The customer was previously subscribed to this list but has unsubscribed themselves.