Squarespace is an all-in-one website platform that has powerful tools and build in functionality. Depending on what you are wanting to accomplish. It provides software as a service for website building and hosting, and allows users to use pre-built website templates and drag-and-drop elements to create and modify webpages. It has e-commerce functionality with builtin SEO, CMS, Analytics, and much more.
Shopify is an all-inclusive online selling platform with a monthly subscription. You can create and develop an online store to promote, sell, and ship your products to customers. Shopify is popular due to its low startup cost and easy-to-use interface.