Klaviyo is the best in class email marketing solution for eCommerce. It's powerful because it connects to your store, and you can create awesome customer segments based on past purchasing behaviors, customer preferences, and even future predictions of spending.
Algolia is search software to improve your in-store search experience, increase conversions and order value. Algolia connects to your product catalog, to provide a frictionless search and navigation experience. Create custom logic to promote specific results and merchandise your collection pages.
Littledata provides a seamless connection between your Shopify site, marketing channels, and Google Analytics to give you the most accurate view of your analytics & performance. It's used heavily by brands who have a mix of single-purchase items and subscriptions on their site.
Shopify is a commerce platform that allows anyone to set up an online store and sell their products. It's the go-to eCommerce platform for young direct-to-consumer brands. It's ease of use and setup is what's most attractive to merchants, but also the incredibly vast Shopify app store.
Webflow commerce is becoming a serious competitor to Shopify. They also boast the ability to create a fully functioning website without touching code, but in addition to that - they pride themselves on giving you the ability to create unique commerce experiences for your customers.
Segment is a Customer Data Platform (CDP). They provide a service that simplifies collecting and using data from the users of your digital properties (websites, apps, etc). With Segment, you can collect, transform, send, and archive your first-party customer data.