Besides Shotify, you can use Magento, 3dcart, Woocommerce, Big Commerce,
And Miva Merchant. It’s expensive but support is top notch, you have access to literally every page and it’s code, it’s written in their own proprietary, compiled .mvc language so it’s fast and secure. I’ve built several stores with Miva. I had a client switch from Miva to Shopify and they immediately got hacked.