Intercom is a Conversational Relationship Platform. It shows you who is using your product or website and makes it easy to personally communicate with them with targeted content, behavior-driven messages, and conversational support.
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.
Heap is an analytics tool that automatically captures all user data on your site. A single snippet grabs every click, swipe, tap and pageview. Heap lets you learn everything about your customers: Who they are, what they do on your site and what actions correlate with conversion & retention.
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.
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.