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.
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.
Trustpilot is a tool to collect reviews from customers. Those reviews are leveraged on-site to increase conversion rates or used to increase visibility with Google. Trustpilot automatically sends review invitation emails and reminders to make it easy for your customers to leave feedback.