Add New Square Customers to Shopify Automatically

Run whenever a new customer profile is created in Square, whether staff added it at the counter or Square created it during a checkout. The profile carries given_name, family_name, email_address, phone_number, address, note and reference_id.

Continue only if the Square profile has an email_address. Square can create profiles during card checkouts that carry no email, and an email is what both stores use to tell one customer from another.

Continue only if the Square profile's reference_id is empty. A filled reference_id means this person was copied from Shopify by the reverse workflow, so there is nothing to create.

Search Shopify customers for the Square profile's email_address, lowercased and trimmed of spaces.

Continue only if the search found no Shopify customer. Shopify allows one customer per email address, so creating a second one would fail.

Create a Shopify customer with the Square first name, last name, email and address, plus the phone number only if it is in +E.164 format. Add the tag square-pos and do not mark the customer as subscribed to email marketing, since Square's consent doesn't carry over.

Update the Square customer profile, setting reference_id to the new Shopify customer ID, so the two records are linked and the reverse workflow can tell this person is already in both stores.