Use this endpoint to create one customer account with its required identity, contact, and address information.

The request body requires first_name, last_name, email, username, address1, city, postal_code, country, and phone. The username must be 3–20 characters and contain only letters, numbers, underscores, or hyphens. Set send_email to control whether Storefront sends an email; it defaults to false.

If your bearer token can access more than one system login, send x-osrs-system-login-id to select the login to use; you can omit this header when exactly one login is available. A successful response returns the new customer's UUID. A 400 response can indicate incomplete onboarding or invalid country, state, postal-code, or currency data; 409 indicates that the username already exists; and 422 indicates a validation error.