Third party integrations
Contrary to most other website builders, there is no app store for adding functionality and third party tools to Squarespace, but you do have the scheduling, email marketing and membership add-ons with additional charges.
Apart from these, you are stuck with the few – but important – integrations available in the account, such as Google tools, social media integrations (Instagram, Facebook, Pinterest, Twitter), Stripe and PayPal.
The Basic and Advanced Commerce plans (not Business) allow integration with ShipStation, which can bulk-print labels for all major shipping carriers.
A limitation of Squarespace is the fact you cannot sync online sales with Xero, unless you use an extension app which Squarespace does not offer direct support for. This makes you reliant on the platform-specific analytics and reports, unless you take a chance with the extensions.
Furthermore, there is no connected POS system available for Squarespace in the UK (there is in the US), so in-person sales cannot be linked to online sales. Other ecommerce platforms like Shopify and Square Online are built to work in unison with a POS system, but Squarespace focuses on online businesses only.